New JoinVarArgsContains inspection that will detect multiple .contains(), .doesNotContain(), and .containsOnlyOnce() calls within the same statement that could be joined together using variadic arguments.

Unrelated: Upgraded Gradle to 5.4.1. Upgraded kotlin to 1.3.40. Upgraded jacoco to 0.8.4. Minor style change for immediate returns. Increased test/branch coverage.

README.md

@@ -79,7 +79,8 @@ You can toggle the various inspections in the Settings/Editor/Inspections in the
   ```
   from: assertThat(expected).someCondition();
         assertThat(expected).anotherCondition();
-    to: assertThat(expected).someCondition().anotherCondition();
+    to: assertThat(expected).someCondition()
+                            .anotherCondition();
   ```
   Joining will work on actual expressions inside ```assertThat()``` that are equivalent expressions,
   except for method calls with known side-effect methods such as ```Iterator.next()``` and
@@ -87,6 +88,26 @@ You can toggle the various inspections in the Settings/Editor/Inspections in the
 
   The comments of the statements will be preserved. When using ```extracting()``` or similar,
   the statements will not be merged.
+  
+  The behavior regarding the insertion of line breaks between the expressions can be configured in the
+  inspection settings.
+
+- JoinVarArgsContains
+
+  Looks for ```.contains()```, ```.doesNotContain()```, and .```containsOnlyOnce()``` calls for iterables 
+  within the same statement. The available quickfix can join the arguments to variadic version of the call
+  and remove the surplus one.
+  
+  ```
+  from: assertThat(expected).contains("foo").doesNotContain("bar").contains("etc").doesNotContain("huh");
+    to: assertThat(expected).contains("foo", "etc").doesNotContain("bar", "huh");
+  ```
+  Will not be performed on more complex statements with ```.extracting()``` or ```.as()``` to avoid
+  changing semantics or losing descriptions.
+
+  Note that the quickfix does not handle comments very well and might remove them during the operation.
+  
+  You may need to perform some manual reformatting, if the line gets too long after applying the fix.
 
 - AssertThatObjectIsNullOrNotNull
 
@@ -339,7 +360,7 @@ You can toggle the various inspections in the Settings/Editor/Inspections in the
     to: assertThat(opt).isPresent();
      
   from: assertThat(opt).isEqualTo(Optional.of("foo"));
-  from: assertThat(opt).isEqualTo(Optional.ofNullable("foo"));
+  from: assertThat(opt).isEqualTo(Optional.ofNullable("foo")); // only for constant "foo"
     to: assertThat(opt).contains("foo"); 
 
   from: assertThat(opt).isEqualTo(Optional.empty());
@@ -376,7 +397,7 @@ You can toggle the various inspections in the Settings/Editor/Inspections in the
     to: assertThat(opt).isPresent();
      
   from: assertThat(opt).isEqualTo(Optional.of("foo"));
-  from: assertThat(opt).isEqualTo(Optional.fromNullable("foo"));
+  from: assertThat(opt).isEqualTo(Optional.fromNullable("foo")); // only for constant "foo"
     to: assertThat(opt).contains("foo"); 
 
   from: assertThat(opt).isEqualTo(Optional.absent());
@@ -505,7 +526,7 @@ The IntelliJ framework actually uses the JUnit 3 TestCase for plugin testing and
 Feel free to use the code (in package ```de.platon42.intellij.jupiter```) for your projects (with attribution).
 
 ## Planned features
-- Joining .contains() expressions
+- More Optional fixes such as opt1.get() == opt2.get() etc.
 - Converting ```foo.compareTo(bar) == 0``` to ```isEqualTo()``` (yes, I've *really* seen code like that)
 - Extraction with property names to lambda with Java 8
 
@@ -516,6 +537,18 @@ Feel free to use the code (in package ```de.platon42.intellij.jupiter```) for yo
 
 ## Changelog
 
+#### V1.3 (03-Aug-19)
+- New JoinVarArgsContains inspection that will detect multiple ```.contains()```, ```.doesNotContain()```,
+  and ```.containsOnlyOnce()``` calls within the same statement that could be joined together using variadic arguments.
+- AssertJ 3.13.0 broke some inspections due to new ```AbstractStringAssert::isEqualTo()``` method.
+- AssertThatJava8Optional and AssertThatGuavaOptional inspections do not longer try to fix
+  ```assertThat(optional).isEqualTo(Optional.fromNullable(expression))``` to ```contains()```
+  when ```expression``` is not a non-null constant expression.
+  
+#### V1.2 (23-Jun-19)
+- Due to popular demand the JoinAssertThatStatements inspection will now add line breaks on joining statements.
+  The amount of statements joined without causing line breaks can be configured but defaults to 1 (always).
+          
 #### V1.1 (09-Jun-19)
 - Improved JoinAssertThatStatements detection of expressions with side-effects and added pre/post-increment/decrement detection.
 - Added Guava Optional ```opt.orNull() == null``` case. You know, I'm not making this stuff up, people actually write this kind of code.

build.gradle

@@ -1,13 +1,13 @@
 plugins {
     id 'java'
     id 'org.jetbrains.intellij' version '0.4.9'
-    id 'org.jetbrains.kotlin.jvm' version '1.3.31'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.41'
     id 'jacoco'
-    id 'com.github.kt3k.coveralls' version '2.8.2'
+    id 'com.github.kt3k.coveralls' version '2.8.4'
 }
 
 group 'de.platon42'
-version '1.1'
+version '1.3'
 
 repositories {
     mavenCentral()
@@ -20,10 +20,10 @@ repositories {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
-    testCompile "org.assertj:assertj-core:3.12.2"
+    testCompile "org.assertj:assertj-core:3.13.0"
     testCompile "org.assertj:assertj-guava:3.2.1"
-    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.5.0-RC1'
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.5.0-RC1'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.5.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.5.1'
     testImplementation "org.jetbrains.kotlin:kotlin-test"
 //    testImplementation "org.jetbrains.kotlin:kotlin-test-junit"
 }
@@ -35,23 +35,22 @@ compileTestKotlin {
     kotlinOptions.jvmTarget = "1.8"
 }
 intellij {
-    version '2019.1.2'
+    version '2019.2'
 //    pluginName 'Concise AssertJ Optimizing Nitpicker (Cajon)'
     updateSinceUntilBuild false
+    plugins = ['java']
 }
 
 patchPluginXml {
     changeNotes """
-  <h4>V1.1 (09-Jun-19)</h4>
+  <h4>V1.3 (03-Aug-19)</h4>
     <ul>
-      <li>Improved JoinAssertThatStatements detection of expressions with side-effects and added pre/post-increment/decrement detection.
-      <li>Added Guava Optional opt.orNull() == null case. You know, I'm not making this stuff up, people actually write this kind of code.
-      <li>Added Java 8 Optional opt.orElse(null) == null case, too.
-      <li>Extended JUnitAssertToAssertJ inspection to convert JUnit assume statements, too.
-      <li>Improved JUnitAssertToAssertJ quick fix to swap expected and actual expressions if the actual one is a constant.
-      <li>New ImplicitAssertion inspection for implicit isNotNull(), isNotEmpty() and isPresent() assertions that will be covered by chained assertions.
-      <li>Fix for multiple JUnit Conversions in batch mode with and without delta creating an exception.
-      <li>Added new AssertThatObjectExpression inspection for toString() and hashCode() and moved equals() from AssertThatBinaryExpression there.
+      <li>New JoinVarArgsContains inspection that will detect multiple .contains(), .doesNotContain(), and .containsOnlyOnce()
+          calls within the same statement that could be joined together using variadic arguments.
+      <li>AssertJ 3.13.0 broke some inspections due to new AbstractStringAssert::isEqualTo() method.
+      <li>AssertThatJava8Optional and AssertThatGuavaOptional inspections do not longer try to fix
+          assertThat(optional).isEqualTo(Optional.fromNullable(expression)) to contains()
+          when expression is not a non-null constant expression.
     </ul>
   <p>Full changelog available at <a href="https://github.com/chrisly42/cajon-plugin#changelog">Github project site</a>.</p>
 """
@@ -65,7 +64,7 @@ test {
 }
 
 jacoco {
-    toolVersion = '0.8.3'
+    toolVersion = '0.8.4'
 }
 
 jacocoTestReport {

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip

src/main/java/de/platon42/intellij/plugins/cajon/CommonMatchers.kt

@@ -36,14 +36,18 @@ val MORE_EXTENSION_POINTS = CallMatcher.instanceCall(
     "hasOnlyOneElementSatisfying", "anyMatch", "noneMatch", "anySatisfy", "noneSatisfy"
 )!!
 
-val NOT_ACTUAL_ASSERTIONS = CallMatcher.anyOf(
-    ALL_ASSERT_THAT_MATCHERS,
+val COMPLEX_CALLS_THAT_MAKES_STUFF_TRICKY = CallMatcher.anyOf(
     DESCRIBED_AS,
     WITH_REPRESENTATION_AND_SUCH,
     USING_COMPARATOR,
     IN_HEXADECIMAL_OR_BINARY
 )!!
 
+val NOT_ACTUAL_ASSERTIONS = CallMatcher.anyOf(
+    ALL_ASSERT_THAT_MATCHERS,
+    COMPLEX_CALLS_THAT_MAKES_STUFF_TRICKY
+)!!
+
 val KNOWN_METHODS_WITH_SIDE_EFFECTS = CallMatcher.anyOf(
     CallMatcher.instanceCall(CommonClassNames.JAVA_UTIL_ITERATOR, "next")
 )!!

src/main/java/de/platon42/intellij/plugins/cajon/Extensions.kt

@@ -106,7 +106,7 @@ fun PsiMethodCallExpression.getExpectedNullNonNullResult(): Boolean? {
     if (isNull || isNotNull) {
         return isNotNull
     } else {
-        val isEqualTo = AbstractAssertJInspection.IS_EQUAL_TO_OBJECT.test(this)
+        val isEqualTo = CallMatcher.anyOf(AbstractAssertJInspection.IS_EQUAL_TO_OBJECT, AbstractAssertJInspection.IS_EQUAL_TO_STRING).test(this)
         val isNotEqualTo = AbstractAssertJInspection.IS_NOT_EQUAL_TO_OBJECT.test(this)
         if ((isEqualTo || isNotEqualTo) && firstArg.type == PsiType.NULL) {
             return isNotEqualTo
@@ -144,9 +144,7 @@ fun PsiExpression.getAllTheSameExpectedBooleanConstants(): Boolean? {
     for (methodCall in methodsToView) {
         val expectedResult = methodCall.getExpectedBooleanResult()
         if (expectedResult != null) {
-            if ((lockedResult != null) && (lockedResult != expectedResult)) {
-                return null
-            }
+            if ((lockedResult != null) && (lockedResult != expectedResult)) return null
             lockedResult = expectedResult
         } else {
             val isNotConstant = CallMatcher.anyOf(
@@ -157,9 +155,7 @@ fun PsiExpression.getAllTheSameExpectedBooleanConstants(): Boolean? {
                 AbstractAssertJInspection.IS_NOT_EQUAL_TO_BOOLEAN,
                 AbstractAssertJInspection.IS_NOT_EQUAL_TO_OBJECT
             ).test(methodCall)
-            if (isNotConstant) {
-                return null
-            }
+            if (isNotConstant) return null
         }
     }
     return lockedResult
@@ -173,9 +169,7 @@ fun PsiExpression.getAllTheSameNullNotNullConstants(): Boolean? {
     for (methodCall in methodsToView) {
         val expectedResult = methodCall.getExpectedNullNonNullResult()
         if (expectedResult != null) {
-            if ((lockedResult != null) && (lockedResult != expectedResult)) {
-                return null
-            }
+            if ((lockedResult != null) && (lockedResult != expectedResult)) return null
             lockedResult = expectedResult
         } else {
             val isNotConstant = CallMatcher.anyOf(
@@ -184,9 +178,7 @@ fun PsiExpression.getAllTheSameNullNotNullConstants(): Boolean? {
                 AbstractAssertJInspection.IS_EQUAL_TO_OBJECT,
                 AbstractAssertJInspection.IS_NOT_EQUAL_TO_OBJECT
             ).test(methodCall)
-            if (isNotConstant) {
-                return null
-            }
+            if (isNotConstant) return null
         }
     }
     return lockedResult

src/main/java/de/platon42/intellij/plugins/cajon/MethodNames.kt

@@ -86,6 +86,8 @@ class MethodNames {
         @NonNls
         const val CONTAINS = "contains"
         @NonNls
+        const val CONTAINS_ONLY_ONCE = "containsOnlyOnce"
+        @NonNls
         const val DOES_NOT_CONTAIN = "doesNotContain"
         @NonNls
         const val CONTAINS_EXACTLY = "containsExactly"

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AbstractAssertJInspection.kt

@@ -13,6 +13,7 @@ import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_A
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_BOOLEAN_ASSERT_CLASSNAME
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_COMPARABLE_ASSERT_CLASSNAME
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_INTEGER_ASSERT_CLASSNAME
+import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_STRING_ASSERT_CLASSNAME
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ASSERTIONS_CLASSNAME
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ASSERT_INTERFACE
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ENUMERABLE_ASSERT_INTERFACE
@@ -81,6 +82,8 @@ open class AbstractAssertJInspection : AbstractBaseJavaLocalInspectionTool() {
 
         val IS_EQUAL_TO_OBJECT = CallMatcher.instanceCall(ASSERT_INTERFACE, MethodNames.IS_EQUAL_TO)
             .parameterTypes(CommonClassNames.JAVA_LANG_OBJECT)!!
+        val IS_EQUAL_TO_STRING = CallMatcher.instanceCall(ABSTRACT_STRING_ASSERT_CLASSNAME, MethodNames.IS_EQUAL_TO)
+            .parameterTypes(CommonClassNames.JAVA_LANG_STRING)!!
         val IS_NOT_EQUAL_TO_OBJECT = CallMatcher.instanceCall(ASSERT_INTERFACE, MethodNames.IS_NOT_EQUAL_TO)
             .parameterTypes(CommonClassNames.JAVA_LANG_OBJECT)!!
         val IS_EQUAL_TO_BOOLEAN = CallMatcher.instanceCall(ABSTRACT_BOOLEAN_ASSERT_CLASSNAME, MethodNames.IS_EQUAL_TO)

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatBinaryExpressionInspection.kt

@@ -21,13 +21,9 @@ class AssertThatBinaryExpressionInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) return
 
                 val expectedCallExpression = statement.findOutmostMethodCall() ?: return
                 val expectedResult = expectedCallExpression.getAllTheSameExpectedBooleanConstants() ?: return
@@ -39,9 +35,9 @@ class AssertThatBinaryExpressionInspection : AbstractAssertJInspection() {
 
                 val bothTypes = listOf(leftType, rightType)
                 val (isLeftNull, isRightNull) = bothTypes.map(TypeConversionUtil::isNullType)
-                if (isLeftNull && isRightNull) {
-                    return
-                } else if (isLeftNull || isRightNull) {
+
+                if (isLeftNull && isRightNull) return
+                if (isLeftNull || isRightNull) {
                     val replacementMethod = expectedResult.map(MethodNames.IS_NULL, MethodNames.IS_NOT_NULL)
                     registerSplitMethod(holder, expectedCallExpression, replacementMethod) { desc, method ->
                         SplitBinaryExpressionMethodCallQuickFix(desc, method, pickRightOperand = isLeftNull, noExpectedExpression = true)

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatBooleanConditionInspection.kt

@@ -20,24 +20,17 @@ class AssertThatBooleanConditionInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val matchingCalls = listOf(
                     IS_EQUAL_TO_OBJECT, IS_EQUAL_TO_BOOLEAN,
                     IS_NOT_EQUAL_TO_OBJECT, IS_NOT_EQUAL_TO_BOOLEAN
                 ).map { it.test(expression) }
-                if (matchingCalls.none { it }) {
-                    return
-                }
-                if (!checkAssertedType(expression, ABSTRACT_BOOLEAN_ASSERT_CLASSNAME)) {
-                    return
-                }
+                if (matchingCalls.none { it }) return
+                if (!checkAssertedType(expression, ABSTRACT_BOOLEAN_ASSERT_CLASSNAME)) return
 
                 val expectedExpression = expression.firstArg
-                if (!TypeConversionUtil.isBooleanType(expectedExpression.type)) {
-                    return
-                }
+                if (!TypeConversionUtil.isBooleanType(expectedExpression.type)) return
+
                 val expectedResult = expression.calculateConstantParameterValue(0) as? Boolean ?: return
                 val flippedBooleanTest = matchingCalls.drop(2).any { it }
 

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatCollectionOrMapExpressionInspection.kt

@@ -44,13 +44,10 @@ class AssertThatCollectionOrMapExpressionInspection : AbstractAssertJInspection(
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) return
+
                 val assertThatArgument = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
                 val mapping = MAPPINGS.firstOrNull { it.callMatcher.test(assertThatArgument) } ?: return
 

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatEnumerableIsEmptyInspection.kt

@@ -21,13 +21,9 @@ class AssertThatEnumerableIsEmptyInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val isLastExpression = expression.parent is PsiStatement
-                if (!(HAS_SIZE.test(expression) && isLastExpression)) {
-                    return
-                }
+                if (!(HAS_SIZE.test(expression) && isLastExpression)) return
 
                 val value = expression.calculateConstantParameterValue(0) ?: return
                 if (value == 0) {

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatGuavaOptionalInspection.kt

@@ -21,20 +21,16 @@ class AssertThatGuavaOptionalInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
 
-                if (!checkPreconditions(staticMethodCall)) {
-                    return
-                }
-                val actualExpression = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
+                if (!checkPreconditions(staticMethodCall)) return
 
+                val actualExpression = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
                 val outmostMethodCall = statement.findOutmostMethodCall() ?: return
                 if (GUAVA_OPTIONAL_GET.test(actualExpression)) {
                     val expectedCallExpression = staticMethodCall.gatherAssertionCalls().singleOrNull() ?: return
-                    if (IS_EQUAL_TO_OBJECT.test(expectedCallExpression)) {
+                    if (CallMatcher.anyOf(IS_EQUAL_TO_OBJECT, IS_EQUAL_TO_STRING).test(expectedCallExpression)) {
                         registerMoveOutMethod(holder, outmostMethodCall, actualExpression, MethodNames.CONTAINS) { desc, method ->
                             QuickFixWithPostfixDelegate(
                                 RemoveActualOutmostMethodCallQuickFix(desc, method),
@@ -65,18 +61,18 @@ class AssertThatGuavaOptionalInspection : AbstractAssertJInspection() {
 
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val staticMethodCall = expression.findStaticMethodCall() ?: return
-                if (!checkPreconditions(staticMethodCall)) {
-                    return
-                }
+                if (!checkPreconditions(staticMethodCall)) return
+
                 // We're not calling an assertThat() from Guava, but a core-AssertJ one!
                 // We need to replace that by the Guava one, if we want to apply a formally correct fix.
                 if (IS_EQUAL_TO_OBJECT.test(expression)) {
                     val innerExpectedCall = expression.firstArg as? PsiMethodCallExpression ?: return
                     if (CallMatcher.anyOf(GUAVA_OPTIONAL_OF, GUAVA_OPTIONAL_FROM_NULLABLE).test(innerExpectedCall)) {
+                        if (GUAVA_OPTIONAL_FROM_NULLABLE.test(innerExpectedCall)) {
+                            innerExpectedCall.firstArg.calculateConstantValue() ?: return
+                        }
                         registerRemoveExpectedOutmostMethod(holder, expression, expression, MethodNames.CONTAINS) { desc, method ->
                             QuickFixWithPostfixDelegate(
                                 UnwrapExpectedStaticMethodCallQuickFix(desc, method),

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatInstanceOfInspection.kt

@@ -20,13 +20,9 @@ class AssertThatInstanceOfInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) return
 
                 val expectedCallExpression = statement.findOutmostMethodCall() ?: return
                 val expectedResult = expectedCallExpression.getAllTheSameExpectedBooleanConstants() ?: return

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatInvertedBooleanConditionInspection.kt

@@ -18,13 +18,9 @@ class AssertThatInvertedBooleanConditionInspection : AbstractAssertJInspection()
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val staticMethodCall = expression.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) return
                 expression.getExpectedBooleanResult() ?: return
 
                 val prefixExpression = staticMethodCall.firstArg as? PsiPrefixExpression ?: return

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatJava8OptionalInspection.kt

@@ -20,19 +20,15 @@ class AssertThatJava8OptionalInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_ANY.test(staticMethodCall)) {
-                    return
-                }
-                val actualExpression = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
+                if (!ASSERT_THAT_ANY.test(staticMethodCall)) return
 
+                val actualExpression = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
                 val outmostMethodCall = statement.findOutmostMethodCall() ?: return
                 if (OPTIONAL_GET.test(actualExpression)) {
                     val expectedCallExpression = staticMethodCall.gatherAssertionCalls().singleOrNull() ?: return
-                    if (IS_EQUAL_TO_OBJECT.test(expectedCallExpression)) {
+                    if (CallMatcher.anyOf(IS_EQUAL_TO_OBJECT, IS_EQUAL_TO_STRING).test(expectedCallExpression)) {
                         registerMoveOutMethod(holder, outmostMethodCall, actualExpression, MethodNames.CONTAINS) { desc, method ->
                             RemoveActualOutmostMethodCallQuickFix(desc, method)
                         }
@@ -58,16 +54,15 @@ class AssertThatJava8OptionalInspection : AbstractAssertJInspection() {
 
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val staticMethodCall = expression.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_JAVA8_OPTIONAL.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_JAVA8_OPTIONAL.test(staticMethodCall)) return
                 if (IS_EQUAL_TO_OBJECT.test(expression)) {
                     val innerExpectedCall = expression.firstArg as? PsiMethodCallExpression ?: return
                     if (CallMatcher.anyOf(OPTIONAL_OF, OPTIONAL_OF_NULLABLE).test(innerExpectedCall)) {
+                        if (OPTIONAL_OF_NULLABLE.test(innerExpectedCall)) {
+                            innerExpectedCall.firstArg.calculateConstantValue() ?: return
+                        }
                         registerRemoveExpectedOutmostMethod(holder, expression, expression, MethodNames.CONTAINS, ::UnwrapExpectedStaticMethodCallQuickFix)
                     } else if (OPTIONAL_EMPTY.test(innerExpectedCall)) {
                         registerSimplifyMethod(holder, expression, MethodNames.IS_NOT_PRESENT)

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatObjectExpressionInspection.kt

@@ -24,9 +24,7 @@ class AssertThatObjectExpressionInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
 
                 val assertThatArgument = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
@@ -40,7 +38,7 @@ class AssertThatObjectExpressionInspection : AbstractAssertJInspection() {
                         }
                     }
                     OBJECT_TO_STRING.test(assertThatArgument) -> {
-                        staticMethodCall.findFluentCallTo(IS_EQUAL_TO_OBJECT) ?: return
+                        staticMethodCall.findFluentCallTo(IS_EQUAL_TO_OBJECT) ?: staticMethodCall.findFluentCallTo(IS_EQUAL_TO_STRING) ?: return
                         registerMoveOutMethod(holder, expectedCallExpression, assertThatArgument, MethodNames.HAS_TO_STRING) { desc, method ->
                             RemoveActualOutmostMethodCallQuickFix(desc, method)
                         }

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatObjectIsNullOrNotNullInspection.kt

@@ -2,6 +2,7 @@ package de.platon42.intellij.plugins.cajon.inspections
 
 import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.psi.*
+import com.siyeh.ig.callMatcher.CallMatcher
 import de.platon42.intellij.plugins.cajon.MethodNames
 import de.platon42.intellij.plugins.cajon.firstArg
 import de.platon42.intellij.plugins.cajon.hasAssertThat
@@ -19,15 +20,11 @@ class AssertThatObjectIsNullOrNotNullInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
                 val isNotEqualTo = IS_NOT_EQUAL_TO_OBJECT.test(expression)
-                val isEqualTo = IS_EQUAL_TO_OBJECT.test(expression)
+                val isEqualTo = CallMatcher.anyOf(IS_EQUAL_TO_OBJECT, IS_EQUAL_TO_STRING).test(expression)
                 val isLastExpression = expression.parent is PsiStatement
-                if (!((isEqualTo && isLastExpression) || isNotEqualTo)) {
-                    return
-                }
+                if (!((isEqualTo && isLastExpression) || isNotEqualTo)) return
 
                 if (expression.firstArg.type == PsiType.NULL) {
                     registerSimplifyMethod(holder, expression, isEqualTo.map(MethodNames.IS_NULL, MethodNames.IS_NOT_NULL))

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatSizeInspection.kt

@@ -74,19 +74,15 @@ class AssertThatSizeInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_INT.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_INT.test(staticMethodCall)) return
+
                 val actualExpression = staticMethodCall.firstArg
                 val isForArrayOrCollection = isArrayLength(actualExpression) || isCollectionSize(actualExpression)
                 val isForString = isCharSequenceLength(actualExpression)
-                if (!(isForArrayOrCollection || isForString)) {
-                    return
-                }
+                if (!(isForArrayOrCollection || isForString)) return
+
                 val matches = staticMethodCall.collectMethodCallsUpToStatement()
                     .mapNotNull { getMatch(it, isForArrayOrCollection, isForString) }
                     .toList()
@@ -112,21 +108,16 @@ class AssertThatSizeInspection : AbstractAssertJInspection() {
 
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
-                if (!HAS_SIZE.test(expression)) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
+                if (!HAS_SIZE.test(expression)) return
                 val actualExpression = expression.firstArg
 
                 val isForArrayOrCollection = isArrayLength(actualExpression) || isCollectionSize(actualExpression)
                 val isForString = isCharSequenceLength(actualExpression)
                 if (!(isForArrayOrCollection
                             || (isForString && checkAssertedType(expression, ABSTRACT_CHAR_SEQUENCE_ASSERT_CLASSNAME)))
-                ) {
-                    return
-                }
+                ) return
+
                 registerConciseMethod(
                     REMOVE_SIZE_DESCRIPTION_TEMPLATE,
                     holder,

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatStringExpressionInspection.kt

@@ -48,13 +48,10 @@ class AssertThatStringExpressionInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitExpressionStatement(statement: PsiExpressionStatement) {
                 super.visitExpressionStatement(statement)
-                if (!statement.hasAssertThat()) {
-                    return
-                }
+                if (!statement.hasAssertThat()) return
                 val staticMethodCall = statement.findStaticMethodCall() ?: return
-                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) {
-                    return
-                }
+                if (!ASSERT_THAT_BOOLEAN.test(staticMethodCall)) return
+
                 val assertThatArgument = staticMethodCall.firstArg as? PsiMethodCallExpression ?: return
                 val mapping = MAPPINGS.firstOrNull { it.callMatcher.test(assertThatArgument) } ?: return
 

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssertThatStringIsEmptyInspection.kt

@@ -5,6 +5,7 @@ import com.intellij.psi.JavaElementVisitor
 import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.PsiMethodCallExpression
 import com.intellij.psi.PsiStatement
+import com.siyeh.ig.callMatcher.CallMatcher
 import de.platon42.intellij.plugins.cajon.AssertJClassNames.Companion.ABSTRACT_CHAR_SEQUENCE_ASSERT_CLASSNAME
 import de.platon42.intellij.plugins.cajon.MethodNames
 import de.platon42.intellij.plugins.cajon.calculateConstantParameterValue
@@ -22,19 +23,13 @@ class AssertThatStringIsEmptyInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
-                val isEqual = IS_EQUAL_TO_OBJECT.test(expression)
+                if (!expression.hasAssertThat()) return
+                val isEqual = CallMatcher.anyOf(IS_EQUAL_TO_OBJECT, IS_EQUAL_TO_STRING).test(expression)
                 val hasSize = HAS_SIZE.test(expression)
                 val isLastExpression = expression.parent is PsiStatement
-                if (!((isEqual || hasSize) && isLastExpression)) {
-                    return
-                }
+                if (!((isEqual || hasSize) && isLastExpression)) return
 
-                if (!checkAssertedType(expression, ABSTRACT_CHAR_SEQUENCE_ASSERT_CLASSNAME)) {
-                    return
-                }
+                if (!checkAssertedType(expression, ABSTRACT_CHAR_SEQUENCE_ASSERT_CLASSNAME)) return
 
                 val value = expression.calculateConstantParameterValue(0) ?: return
                 if ((isEqual && (value == "")) || (hasSize && (value == 0))) {

src/main/java/de/platon42/intellij/plugins/cajon/inspections/AssumeThatInsteadOfReturnInspection.kt

@@ -54,9 +54,7 @@ class AssumeThatInsteadOfReturnInspection : AbstractAssertJInspection() {
                 super.visitMethod(method)
                 // Note: replace with if(TEST_ANNOTATIONS.none(method::hasAnnotation)) for IDEA >= 2018.2
                 val annotations = method.annotations.mapNotNull { it.qualifiedName }
-                if (annotations.none(TEST_ANNOTATIONS::contains)) {
-                    return
-                }
+                if (annotations.none(TEST_ANNOTATIONS::contains)) return
                 val containingClass = method.containingClass ?: return
                 val visitor: PsiElementVisitor = TestMethodVisitor(holder, isOnTheFly, containingClass)
                 method.accept(visitor)
@@ -119,9 +117,7 @@ class AssumeThatInsteadOfReturnInspection : AbstractAssertJInspection() {
         var aborted = false
 
         override fun visitExpressionStatement(statement: PsiExpressionStatement) {
-            if (foundAssertThat || aborted) {
-                return
-            }
+            if (foundAssertThat || aborted) return
             if (++statementCount > MAX_STATEMENTS_COUNT) {
                 aborted = true
                 return

src/main/java/de/platon42/intellij/plugins/cajon/inspections/ImplicitAssertionInspection.kt

@@ -29,7 +29,7 @@ class ImplicitAssertionInspection : AbstractAssertJInspection() {
 
         private val OBJECT_ENUMERABLE_ANY_CONTENT_ASSERTIONS = CallMatcher.instanceCall(
             AssertJClassNames.OBJECT_ENUMERABLE_ASSERT_INTERFACE,
-            MethodNames.CONTAINS, "containsOnly", "containsOnlyNulls", "containsOnlyOnce",
+            MethodNames.CONTAINS, "containsOnly", "containsOnlyNulls", MethodNames.CONTAINS_ONLY_ONCE,
             "containsExactly", "containsExactlyInAnyOrder", "containsExactlyInAnyOrderElementsOf",
             "containsAll", "containsAnyOf",
             "containsAnyElementsOf", "containsExactlyElementsOf", "containsOnlyElementsOf",
@@ -113,9 +113,8 @@ class ImplicitAssertionInspection : AbstractAssertJInspection() {
         return object : JavaElementVisitor() {
             override fun visitMethodCallExpression(expression: PsiMethodCallExpression) {
                 super.visitMethodCallExpression(expression)
-                if (!expression.hasAssertThat()) {
-                    return
-                }
+                if (!expression.hasAssertThat()) return
+
                 val mapping = MAPPINGS.firstOrNull { it.first.test(expression) } ?: return
                 val followupExpression = expression.findFluentCallTo(mapping.second) ?: return
                 val redundantName = getOriginalMethodName(expression) ?: return

src/main/java/de/platon42/intellij/plugins/cajon/inspections/JoinAssertThatStatementsInspection.kt

@@ -2,19 +2,25 @@ package de.platon42.intellij.plugins.cajon.inspections
 
 import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.codeInspection.ui.SingleIntegerFieldOptionsPanel
 import com.intellij.psi.*
 import com.intellij.psi.util.PsiTreeUtil
 import com.siyeh.ig.psiutils.EquivalenceChecker
 import de.platon42.intellij.plugins.cajon.*
 import de.platon42.intellij.plugins.cajon.quickfixes.JoinStatementsQuickFix
+import javax.swing.JComponent
 
 class JoinAssertThatStatementsInspection : AbstractAssertJInspection() {
 
     companion object {
         private const val DISPLAY_NAME = "Join multiple assertThat() statements with same actual expression"
         private const val CAN_BE_JOINED_DESCRIPTION = "Multiple assertThat() statements can be joined together"
+        private const val DEFAULT_SEPARATE_LINE_LIMIT = 1
     }
 
+    @JvmField
+    var separateLineLimit: Int = DEFAULT_SEPARATE_LINE_LIMIT
+
     override fun getDisplayName() = DISPLAY_NAME
 
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
@@ -63,9 +69,8 @@ class JoinAssertThatStatementsInspection : AbstractAssertJInspection() {
 
             private fun isLegitAssertThatCall(statement: PsiStatement?): PsiMethodCallExpression? {
                 if ((statement is PsiExpressionStatement) && (statement.expression is PsiMethodCallExpression)) {
-                    if (!statement.hasAssertThat()) {
-                        return null
-                    }
+                    if (!statement.hasAssertThat()) return null
+
                     val assertThatCall = PsiTreeUtil.findChildrenOfType(statement, PsiMethodCallExpression::class.java).find { ALL_ASSERT_THAT_MATCHERS.test(it) }
                     return assertThatCall?.takeIf { it.findFluentCallTo(EXTRACTING_CALL_MATCHERS) == null }
                 }
@@ -93,6 +98,10 @@ class JoinAssertThatStatementsInspection : AbstractAssertJInspection() {
         }
     }
 
+    override fun createOptionsPanel(): JComponent {
+        return SingleIntegerFieldOptionsPanel("Limit for joins before adding line breaks:", this, "separateLineLimit")
+    }
+
     private fun registerProblem(holder: ProblemsHolder, isOnTheFly: Boolean, firstStatement: PsiStatement, lastStatement: PsiStatement) {
         val problemDescriptor = holder.manager.createProblemDescriptor(
             firstStatement,
@@ -100,7 +109,7 @@ class JoinAssertThatStatementsInspection : AbstractAssertJInspection() {
             CAN_BE_JOINED_DESCRIPTION,
             ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
             isOnTheFly,
-            JoinStatementsQuickFix()
+            JoinStatementsQuickFix(separateLineLimit)
         )
         holder.registerProblem(problemDescriptor)
     }

src/main/java/de/platon42/intellij/plugins/cajon/inspections/JoinVarArgsContainsInspection.kt

@@ -0,0 +1,53 @@
+package de.platon42.intellij.plugins.cajon.inspections
+
+import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.openapi.util.TextRange
+import com.intellij.psi.JavaElementVisitor
+import com.intellij.psi.PsiElementVisitor
+import com.intellij.psi.PsiExpressionStatement
+import com.intellij.psi.PsiMethodCallExpression
+import com.intellij.psi.util.PsiTreeUtil
+import com.siyeh.ig.callMatcher.CallMatcher
+import de.platon42.intellij.plugins.cajon.*
+import de.platon42.intellij.plugins.cajon.quickfixes.JoinVarArgsContainsQuickFix
+
+class JoinVarArgsContainsInspection : AbstractAssertJInspection() {
+
+    companion object {
+        private const val DISPLAY_NAME = "Join variadic arguments of contains()/containsOnlyOnce()/doesNotContain()"
+        private const val JOIN_VARARGS_MESSAGE = "Calls to same methods may be joined to variadic version"
+
+        private val MATCHERS = listOf(MethodNames.CONTAINS, MethodNames.CONTAINS_ONLY_ONCE, MethodNames.DOES_NOT_CONTAIN)
+            .map { CallMatcher.instanceCall(AssertJClassNames.ABSTRACT_ITERABLE_ASSERT_CLASSNAME, it) }
+    }
+
+    override fun getDisplayName() = DISPLAY_NAME
+
+    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
+        return object : JavaElementVisitor() {
+            override fun visitExpressionStatement(statement: PsiExpressionStatement) {
+                super.visitStatement(statement)
+                if (!statement.hasAssertThat()) return
+                val assertThatCall = PsiTreeUtil.findChildrenOfType(statement, PsiMethodCallExpression::class.java).find { ALL_ASSERT_THAT_MATCHERS.test(it) } ?: return
+
+                val allCalls = assertThatCall.collectMethodCallsUpToStatement().toList()
+
+                if (allCalls.find(COMPLEX_CALLS_THAT_MAKES_STUFF_TRICKY::test) != null) return
+
+                val onlyAssertionCalls = allCalls
+                    .filterNot { NOT_ACTUAL_ASSERTIONS.test(it) }
+                    .toList()
+
+                for (methodMatcher in MATCHERS) {
+                    if (onlyAssertionCalls.count(methodMatcher::test) > 1) {
+                        val outmostMethodCall = statement.findOutmostMethodCall() ?: return
+                        val quickFix = JoinVarArgsContainsQuickFix(MATCHERS)
+                        val textRange = TextRange(outmostMethodCall.qualifierExpression.textLength, outmostMethodCall.textLength)
+                        holder.registerProblem(outmostMethodCall, textRange, JOIN_VARARGS_MESSAGE, quickFix)
+                        return
+                    }
+                }
+            }
+        }
+    }
+}

src/main/java/de/platon42/intellij/plugins/cajon/quickfixes/JoinStatementsQuickFix.kt

@@ -7,7 +7,7 @@ import com.intellij.psi.util.PsiTreeUtil
 import de.platon42.intellij.plugins.cajon.findStaticMethodCall
 import de.platon42.intellij.plugins.cajon.shortenAndReformat
 
-class JoinStatementsQuickFix : AbstractCommonQuickFix(JOIN_STATEMENTS_MESSAGE) {
+class JoinStatementsQuickFix(private val separateLineLimit: Int) : AbstractCommonQuickFix(JOIN_STATEMENTS_MESSAGE) {
 
     companion object {
         private const val JOIN_STATEMENTS_MESSAGE = "Join assertThat() statements"
@@ -16,6 +16,10 @@ class JoinStatementsQuickFix : AbstractCommonQuickFix(JOIN_STATEMENTS_MESSAGE) {
     override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
         val firstStatement = descriptor.startElement as PsiExpressionStatement
         val lastStatement = descriptor.endElement as PsiExpressionStatement
+
+        val expressionCount = countExpressions(firstStatement, lastStatement)
+        val addLineBreaks = (expressionCount > separateLineLimit)
+
         do {
             val commentsToKeep = ArrayList<PsiComment>()
             val stuffToDelete = ArrayList<PsiElement>()
@@ -37,10 +41,10 @@ class JoinStatementsQuickFix : AbstractCommonQuickFix(JOIN_STATEMENTS_MESSAGE) {
             val lastElementBeforeConcat = assertThatCallOfCursorStatement.parent
             commentsToKeep.forEach {
                 lastElementBeforeConcat.addAfter(it, lastElementBeforeConcat.firstChild)
-                val newLineNode =
-                    PsiParserFacade.SERVICE.getInstance(project).createWhiteSpaceFromText("\n\t")
-
-                lastElementBeforeConcat.addAfter(newLineNode, lastElementBeforeConcat.firstChild)
+                addLineBreak(project, lastElementBeforeConcat)
+            }
+            if (commentsToKeep.isEmpty() && addLineBreaks) {
+                addLineBreak(project, lastElementBeforeConcat)
             }
 
             val newLeaf = previousStatement.firstChild
@@ -50,4 +54,27 @@ class JoinStatementsQuickFix : AbstractCommonQuickFix(JOIN_STATEMENTS_MESSAGE) {
         val codeBlock = PsiTreeUtil.getParentOfType(lastStatement, PsiCodeBlock::class.java) ?: return
         codeBlock.shortenAndReformat()
     }
+
+    private fun addLineBreak(project: Project, lastElementBeforeConcat: PsiElement) {
+        val newLineNode =
+            PsiParserFacade.SERVICE.getInstance(project).createWhiteSpaceFromText("\n\t")
+
+        lastElementBeforeConcat.addAfter(newLineNode, lastElementBeforeConcat.firstChild)
+    }
+
+    private fun countExpressions(firstStatement: PsiElement, lastStatement: PsiElement): Int {
+        var count = 0
+        var currentStatement = firstStatement
+        do {
+            while (currentStatement !is PsiExpressionStatement) {
+                currentStatement = currentStatement.nextSibling!!
+            }
+            count++
+            if (currentStatement === lastStatement) {
+                break
+            }
+            currentStatement = currentStatement.nextSibling!!
+        } while (true)
+        return count
+    }
 }

src/main/java/de/platon42/intellij/plugins/cajon/quickfixes/JoinVarArgsContainsQuickFix.kt

@@ -0,0 +1,38 @@
+package de.platon42.intellij.plugins.cajon.quickfixes
+
+import com.intellij.codeInspection.ProblemDescriptor
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiMethodCallExpression
+import com.siyeh.ig.callMatcher.CallMatcher
+import de.platon42.intellij.plugins.cajon.*
+
+class JoinVarArgsContainsQuickFix(private val matchers: Iterable<CallMatcher>) : AbstractCommonQuickFix(JOIN_VARARGS_DESCRIPTION) {
+
+    companion object {
+        private const val JOIN_VARARGS_DESCRIPTION = "Join multiple arguments to variadic argument method calls"
+    }
+
+    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+        var outmostCallExpression = descriptor.startElement as? PsiMethodCallExpression ?: return
+
+        for (matcher in matchers) {
+            val assertThatMethodCall = outmostCallExpression.findStaticMethodCall() ?: return
+            val methodsToFix = assertThatMethodCall.gatherAssertionCalls()
+            val matchedCalls = methodsToFix.filter(matcher::test)
+            if (matchedCalls.size > 1) {
+                val mainCall = matchedCalls.first()
+                val args = mutableListOf(*mainCall.argumentList.expressions)
+                for (secondaryCall in matchedCalls.asSequence().drop(1)) {
+                    args.addAll(secondaryCall.argumentList.expressions)
+                }
+                val newMainCall = createExpectedMethodCall(mainCall, mainCall.methodExpression.qualifiedName, *args.toTypedArray())
+                newMainCall.replaceQualifierFromMethodCall(mainCall)
+                mainCall.replace(newMainCall)
+                for (secondaryCall in matchedCalls.asSequence().drop(1)) {
+                    val newQualifier = secondaryCall.qualifierExpression
+                    outmostCallExpression = secondaryCall.replace(newQualifier).findOutmostMethodCall() ?: return
+                }
+            }
+        }
+    }
+}

src/main/java/de/platon42/intellij/plugins/cajon/references/ExtractorReferenceContributor.kt

@@ -56,11 +56,9 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
 
         private fun findAndCreateReferences(element: PsiElement, finder: (PsiLiteralExpression) -> List<Pair<TextRange, List<PsiElement>>>?): Array<PsiReference> {
             val literal = element as PsiLiteralExpression
-            val results = finder(literal)
-            if (results != null) {
-                return results.map { ExtractorReference(literal, it.first, it.second) }.toTypedArray()
-            }
-            return PsiReference.EMPTY_ARRAY
+            val results = finder(literal) ?: return PsiReference.EMPTY_ARRAY
+
+            return results.map { ExtractorReference(literal, it.first, it.second) }.toTypedArray()
         }
     }
 
@@ -73,6 +71,7 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
     class ExtractorReference(literal: PsiLiteralExpression, range: TextRange, private val targets: List<PsiElement>) :
         PsiPolyVariantReferenceBase<PsiLiteralExpression>(literal, range, true) {
 
+        // Do not remove due to compatiblity issue with IDEA <= 2018.2
         override fun getVariants(): Array<Any> {
             return ArrayUtil.EMPTY_OBJECT_ARRAY
         }
@@ -88,9 +87,7 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
 
     class PropertyOrFieldReferenceProvider : PsiReferenceProvider() {
 
-        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> {
-            return findAndCreateReferences(element, ::findReferences)
-        }
+        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> = findAndCreateReferences(element, ::findReferences)
 
         fun findReferences(element: PsiLiteralExpression): List<Pair<TextRange, List<PsiElement>>>? {
             val literal = element.value as? String ?: return null
@@ -112,9 +109,7 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
 
     class IterablePropertyOrFieldReferenceProvider : PsiReferenceProvider() {
 
-        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> {
-            return findAndCreateReferences(element, ::findReferences)
-        }
+        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> = findAndCreateReferences(element, ::findReferences)
 
         fun findReferences(element: PsiLiteralExpression): List<Pair<TextRange, List<PsiElement>>>? {
             val literal = element.value as? String ?: return null
@@ -127,9 +122,8 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
                 isResultOf = true
             }
 
-            if (!CallMatcher.anyOf(EXTRACTING_FROM_ITERABLE, FLAT_EXTRACTING_FROM_ITERABLE).test(methodCallExpression)) {
-                return null
-            }
+            if (!CallMatcher.anyOf(EXTRACTING_FROM_ITERABLE, FLAT_EXTRACTING_FROM_ITERABLE).test(methodCallExpression)) return null
+
             val iterableType = findActualType(methodCallExpression) ?: return null
             val innerType = iterableType.resolveGenerics().substitutor.substitute(iterableType.parameters[0])
             val containingClass = PsiTypesUtil.getPsiClass(innerType) ?: return null
@@ -139,16 +133,13 @@ class ExtractorReferenceContributor : PsiReferenceContributor() {
 
     class IterableResultOfReferenceProvider : PsiReferenceProvider() {
 
-        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> {
-            return findAndCreateReferences(element, ::findReferences)
-        }
+        override fun getReferencesByElement(element: PsiElement, context: ProcessingContext): Array<PsiReference> = findAndCreateReferences(element, ::findReferences)
 
         fun findReferences(element: PsiLiteralExpression): List<Pair<TextRange, List<PsiElement>>>? {
             val literal = element.value as? String ?: return null
             val methodCallExpression = PsiTreeUtil.getParentOfType(element, PsiMethodCallExpression::class.java) ?: return null
-            if (!EXTRACTING_RESULT_OF_FROM_ITERABLE.test(methodCallExpression)) {
-                return null
-            }
+            if (!EXTRACTING_RESULT_OF_FROM_ITERABLE.test(methodCallExpression)) return null
+
             val iterableType = findActualType(methodCallExpression) ?: return null
             val innerType = iterableType.resolveGenerics().substitutor.substitute(iterableType.parameters[0])
             val containingClass = PsiTypesUtil.getPsiClass(innerType) ?: return null

src/main/resources/META-INF/plugin.xml

@@ -1,21 +1,20 @@
 <idea-plugin>
     <id>de.platon42.cajon</id>
     <name>Concise AssertJ Optimizing Nitpicker (Cajon)</name>
-    <vendor email="chrisly@platon42.de" url="https://github.com/chrisly42/cajon-plugin">Platon42</vendor>
+    <vendor email="chrisly@platon42.de" url="https://github.com/chrisly42/cajon-plugin">Chris 'platon42' Hodges</vendor>
 
     <description><![CDATA[
     Cajon is an IntelliJ IDEA Plugin for shortening and optimizing AssertJ assertions.
     It adds several inspections and quick fixes to fully use the fluent assertion methods
     and thus makes the intention clear and concise, also generating better messages on test failures.
-    It can also be used to convert JUnit 4 assertions to AssertJ.
+    It can also be used to convert JUnit 4 assertions and assumptions to AssertJ.
     It supports referencing inside extracting()-methods with strings, adding refactoring safety.
+    <p>
+    <a href="https://github.com/chrisly42/cajon-plugin/blob/master/README.md">Full documentation here...</a>
     ]]></description>
 
-    <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/build_number_ranges.html for description -->
     <idea-version since-build="173.2696.26"/>
 
-    <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/plugin_compatibility.html
-         on how to target different products -->
     <depends>com.intellij.modules.lang</depends>
     <depends>com.intellij.modules.platform</depends>
     <depends>com.intellij.modules.java</depends>
@@ -49,6 +48,8 @@
 
         <localInspection groupPath="Java" shortName="JoinAssertThatStatements" enabledByDefault="true" level="WARNING"
                          implementationClass="de.platon42.intellij.plugins.cajon.inspections.JoinAssertThatStatementsInspection"/>
+        <localInspection groupPath="Java" shortName="JoinVarArgsContains" enabledByDefault="true" level="WARNING"
+                         implementationClass="de.platon42.intellij.plugins.cajon.inspections.JoinVarArgsContainsInspection"/>
         <localInspection groupPath="Java" shortName="AssumeThatInsteadOfReturn" enabledByDefault="true" level="WARNING"
                          implementationClass="de.platon42.intellij.plugins.cajon.inspections.AssumeThatInsteadOfReturnInspection"/>
 

src/main/resources/inspectionDescriptions/JoinAssertThatStatements.html

@@ -2,6 +2,9 @@
 <body>
 Joins consecutive assertThat() statements with the same actual expression together.
 <!-- tooltip end -->
-<br>Retains comments during operation. If the AssertThat()-Statement contains .extracting() methods, they will not be joined.
+<br>If the AssertThat()-Statement contains .extracting() methods, they will not be joined.
+<br>During joining multiple statements, line breaks may be added to avoid too long lines. The number of statements to join without
+adding line breaks can be configured.
+<br>Also retains comments during operation and forces a line break for these cases.
 </body>
 </html>

src/main/resources/inspectionDescriptions/JoinVarArgsContains.html

@@ -0,0 +1,11 @@
+<html>
+<body>
+Finds assertions where multiple .contains(), .containsOnlyOnce() or .doesNotContain() are
+used in a single statement that could be joined together.
+<!-- tooltip end -->
+Only works when variadic arguments are possible and will not be performed on more complex
+statements with .extracting() or .as() to avoid changing semantics.
+<br>
+Note that the quickfix does not handle comments very well and might remove them during the operation.
+</body>
+</html>

src/test/java/de/platon42/intellij/jupiter/LightCodeInsightExtension.java

@@ -11,7 +11,7 @@ import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.testFramework.*;
 import com.intellij.testFramework.fixtures.IdeaTestExecutionPolicy;
 import com.intellij.testFramework.fixtures.JavaCodeInsightTestFixture;
-import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase;
+import com.intellij.testFramework.fixtures.LightJavaCodeInsightFixtureTestCase;
 import org.jetbrains.annotations.NotNull;
 import org.junit.jupiter.api.extension.*;
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
@@ -88,7 +88,6 @@ public class LightCodeInsightExtension implements ParameterResolver, AfterTestEx
                 TestLoggerFactory.onTestFinished(true);
             } catch (Throwable e) {
                 TestLoggerFactory.onTestFinished(false);
-                e.fillInStackTrace();
                 throwables[0] = e;
             }
         };
@@ -112,7 +111,7 @@ public class LightCodeInsightExtension implements ParameterResolver, AfterTestEx
         }
     }
 
-    private static class LightCodeInsightFixtureTestCaseWrapper extends LightCodeInsightFixtureTestCase {
+    private static class LightCodeInsightFixtureTestCaseWrapper extends LightJavaCodeInsightFixtureTestCase {
         private final ExtensionContext extensionContext;
 
         private LightCodeInsightFixtureTestCaseWrapper(ExtensionContext extensionContext) {
@@ -159,7 +158,7 @@ public class LightCodeInsightExtension implements ParameterResolver, AfterTestEx
             };
         }
 
-        protected void addJarContaining(ModifiableRootModel model, Class clazz) {
+        void addJarContaining(ModifiableRootModel model, Class clazz) {
             try {
                 Path jarPath = Paths.get(clazz.getProtectionDomain().getCodeSource().getLocation().toURI());
 

src/test/java/de/platon42/intellij/plugins/cajon/AbstractCajonTest.kt

@@ -23,6 +23,7 @@ abstract class AbstractCajonTest {
     protected fun executeQuickFixes(myFixture: JavaCodeInsightTestFixture, regex: Regex, expectedFixes: Int) {
         val quickfixes = myFixture.getAllQuickFixes().filter { it.text.matches(regex) }
         assertThat(quickfixes).`as`("Fixes matched by $regex: ${myFixture.getAllQuickFixes().map { it.text }}").hasSize(expectedFixes)
+        quickfixes.forEach { it.familyName }
         quickfixes.forEach(myFixture::launchAction)
     }
 

src/test/java/de/platon42/intellij/plugins/cajon/inspections/JoinVarArgsContainsInspectionTest.kt

@@ -0,0 +1,19 @@
+package de.platon42.intellij.plugins.cajon.inspections
+
+import com.intellij.testFramework.fixtures.JavaCodeInsightTestFixture
+import de.platon42.intellij.jupiter.MyFixture
+import de.platon42.intellij.jupiter.TestDataSubPath
+import de.platon42.intellij.plugins.cajon.AbstractCajonTest
+import org.junit.jupiter.api.Test
+
+internal class JoinVarArgsContainsInspectionTest : AbstractCajonTest() {
+
+    @Test
+    @TestDataSubPath("inspections/JoinVarArgsContains")
+    internal fun join_contains_and_doesNotContain_together_where_possible(@MyFixture myFixture: JavaCodeInsightTestFixture) {
+        myFixture.enableInspections(JoinVarArgsContainsInspection::class.java)
+        myFixture.configureByFile("JoinVarArgsContainsBefore.java")
+        executeQuickFixes(myFixture, Regex.fromLiteral("Join multiple arguments to variadic argument method calls"), 3)
+        myFixture.checkResultByFile("JoinVarArgsContainsAfter.java")
+    }
+}

src/test/java/de/platon42/intellij/plugins/cajon/references/ExtractorReferenceContributorTest.kt

@@ -5,6 +5,7 @@ import de.platon42.intellij.jupiter.MyFixture
 import de.platon42.intellij.jupiter.TestDataSubPath
 import de.platon42.intellij.plugins.cajon.AbstractCajonTest
 import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatThrownBy
 import org.junit.jupiter.api.Test
 
 
@@ -70,4 +71,10 @@ internal class ExtractorReferenceContributorTest : AbstractCajonTest() {
         myFixture.configureByFiles("FindReference10.java", "Address.java", "Contact.java")
         assertThat(myFixture.elementAtCaret.text).startsWith("public String getStreetName()")
     }
+
+    @Test
+    internal fun extractor_is_unable_to_find_reference(@MyFixture myFixture: JavaCodeInsightTestFixture) {
+        myFixture.configureByFiles("FindReference11.java", "Address.java", "Contact.java")
+        assertThatThrownBy { myFixture.elementAtCaret.text }.isInstanceOf(AssertionError::class.java)
+    }
 }

src/test/resources/inspections/BinaryExpression/BinaryExpressionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class BinaryExpression {
 
@@ -195,5 +196,8 @@ public class BinaryExpression {
         assertThat(primAct == primExp).isFalse().as("doh!").isEqualTo(true);
 
         assertThat(numberObjAct.equals(numberObjExp)).as("doh!").isTrue().isEqualTo(true);
+
+        org.junit.Assert.assertThat(stringAct, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/BinaryExpression/BinaryExpressionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class BinaryExpression {
 
@@ -195,5 +196,8 @@ public class BinaryExpression {
         assertThat(primAct == primExp).isFalse().as("doh!").isEqualTo(true);
 
         assertThat(numberObjAct.equals(numberObjExp)).as("doh!").isTrue().isEqualTo(true);
+
+        org.junit.Assert.assertThat(stringAct, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/BooleanCondition/BooleanConditionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class BooleanCondition {
 
@@ -30,5 +31,9 @@ public class BooleanCondition {
         assertThat("").isEqualTo(Boolean.TRUE);
 
         assertThat(primitive).isTrue().as("foo").isTrue().as("bar").isTrue().isFalse();
+
+        assertThat(object).isEqualTo(Boolean.TYPE);
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/BooleanCondition/BooleanConditionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class BooleanCondition {
 
@@ -30,5 +31,9 @@ public class BooleanCondition {
         assertThat("").isEqualTo(Boolean.TRUE);
 
         assertThat(primitive).isEqualTo(Boolean.TRUE).as("foo").isEqualTo(true).as("bar").isTrue().isFalse();
+
+        assertThat(object).isEqualTo(Boolean.TYPE);
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/CollectionMapExpression/CollectionMapExpressionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.util.*;
 
@@ -40,5 +41,8 @@ public class CollectionMapExpression {
         assertThat(stringList).as("foo").isNotEmpty().as("bar").isNotEmpty();
         assertThat(stringList.isEmpty()).as("foo").isEqualTo(false).as("bar").isTrue();
         assertThat(stringList.isEmpty()).as("foo").satisfies(it -> it.booleanValue()).as("bar").isFalse();
+
+        org.junit.Assert.assertThat(stringList, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/CollectionMapExpression/CollectionMapExpressionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.util.*;
 
@@ -40,5 +41,8 @@ public class CollectionMapExpression {
         assertThat(stringList.isEmpty()).as("foo").isEqualTo(false).as("bar").isFalse();
         assertThat(stringList.isEmpty()).as("foo").isEqualTo(false).as("bar").isTrue();
         assertThat(stringList.isEmpty()).as("foo").satisfies(it -> it.booleanValue()).as("bar").isFalse();
+
+        org.junit.Assert.assertThat(stringList, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/EnumerableIsEmpty/EnumerableIsEmptyAfter.java

@@ -1,6 +1,7 @@
 import java.util.ArrayList;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class EnumerableIsEmpty {
 
@@ -16,5 +17,8 @@ public class EnumerableIsEmpty {
         assertThat(new Long[1]).as("etc").hasSize(1);
 
         assertThat("string").as("foo").hasSize(0).hasSameSizeAs("foo").isEmpty();
+
+        org.junit.Assert.assertThat("foo", null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/EnumerableIsEmpty/EnumerableIsEmptyBefore.java

@@ -1,6 +1,7 @@
 import java.util.ArrayList;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class EnumerableIsEmpty {
 
@@ -16,5 +17,8 @@ public class EnumerableIsEmpty {
         assertThat(new Long[1]).as("etc").hasSize(1);
 
         assertThat("string").as("foo").hasSize(0).hasSameSizeAs("foo").hasSize(0);
+
+        org.junit.Assert.assertThat("foo", null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/GuavaOptional/GuavaOptionalAfter.java

@@ -1,6 +1,7 @@
 import com.google.common.base.Optional;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.assertj.guava.api.Assertions.assertThat;
 
 public class GuavaOptional {
@@ -30,8 +31,21 @@ public class GuavaOptional {
         assertThat(opt).isPresent();
         assertThat(opt).isPresent();
 
+        //assertThat(opt.get()).isEqualTo(opt.get()); // there's a better version than contains(opt.get())
+        assertThat(opt.orNull()).isEqualTo(opt.get());
+        //assertThat(opt.get()).isEqualTo(opt.orNull()); // there's a better version than contains(opt.orNull())
+
+        assertThat(opt).contains(opt.get());
+        assertThat(opt).contains(opt.orNull());
+
+        String possibleNullString = System.getProperty("username");
+        String notNullString = "Narf";
+
         assertThat(opt).as("foo").contains("foo");
         assertThat(opt).contains("foo");
+        assertThat(opt).isEqualTo(Optional.fromNullable(null));
+        assertThat(opt).isEqualTo(Optional.fromNullable(possibleNullString));
+        assertThat(opt).isEqualTo(Optional.fromNullable(notNullString));
         assertThat(opt).isNotEqualTo(Optional.of("foo"));
         assertThat(opt).isNotEqualTo(Optional.fromNullable("foo"));
 
@@ -56,5 +70,10 @@ public class GuavaOptional {
 
         assertThat(opt).as("foo").isPresent().as("bar").isPresent();
         assertThat(opt.isPresent()).as("foo").isEqualTo(true).as("bar").isEqualTo(Boolean.FALSE);
+
+        assertThat(opt.orNull()).as("foo").isEqualTo(null).isNotNull();
+
+        org.junit.Assert.assertThat(opt, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/GuavaOptional/GuavaOptionalBefore.java

@@ -1,6 +1,7 @@
 import com.google.common.base.Optional;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.assertj.guava.api.Assertions.assertThat;
 
 public class GuavaOptional {
@@ -30,8 +31,21 @@ public class GuavaOptional {
         assertThat(opt.orNull()).isNotEqualTo(null);
         assertThat(opt.orNull()).isNotNull();
 
+        //assertThat(opt.get()).isEqualTo(opt.get()); // there's a better version than contains(opt.get())
+        assertThat(opt.orNull()).isEqualTo(opt.get());
+        //assertThat(opt.get()).isEqualTo(opt.orNull()); // there's a better version than contains(opt.orNull())
+
+        assertThat(opt).contains(opt.get());
+        assertThat(opt).contains(opt.orNull());
+
+        String possibleNullString = System.getProperty("username");
+        String notNullString = "Narf";
+
         assertThat(opt).as("foo").isEqualTo(Optional.of("foo"));
         assertThat(opt).isEqualTo(Optional.fromNullable("foo"));
+        assertThat(opt).isEqualTo(Optional.fromNullable(null));
+        assertThat(opt).isEqualTo(Optional.fromNullable(possibleNullString));
+        assertThat(opt).isEqualTo(Optional.fromNullable(notNullString));
         assertThat(opt).isNotEqualTo(Optional.of("foo"));
         assertThat(opt).isNotEqualTo(Optional.fromNullable("foo"));
 
@@ -56,5 +70,10 @@ public class GuavaOptional {
 
         assertThat(opt.isPresent()).as("foo").isEqualTo(true).as("bar").isEqualTo(Boolean.TRUE);
         assertThat(opt.isPresent()).as("foo").isEqualTo(true).as("bar").isEqualTo(Boolean.FALSE);
+
+        assertThat(opt.orNull()).as("foo").isEqualTo(null).isNotNull();
+
+        org.junit.Assert.assertThat(opt, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/ImplicitAssertion/ImplicitAssertionAfter.java

@@ -6,6 +6,7 @@ import java.util.Optional;
 import java.util.function.Consumer;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.assertj.guava.api.Assertions.assertThat;
 
 public class ImplicitAssertion {
@@ -284,5 +285,8 @@ public class ImplicitAssertion {
         assertThat(guavaOptional).contains("foo");
         assertThat(guavaOptional).extractingValue().isEqualTo("foo");
         assertThat(guavaOptional).extractingCharSequence().isEqualTo("foo");
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/ImplicitAssertion/ImplicitAssertionBefore.java

@@ -6,6 +6,7 @@ import java.util.Optional;
 import java.util.function.Consumer;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.assertj.guava.api.Assertions.assertThat;
 
 public class ImplicitAssertion {
@@ -284,5 +285,8 @@ public class ImplicitAssertion {
         assertThat(guavaOptional).isPresent().contains("foo");
         assertThat(guavaOptional).isPresent().extractingValue().isEqualTo("foo");
         assertThat(guavaOptional).isPresent().extractingCharSequence().isEqualTo("foo");
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/InstanceOf/InstanceOfAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class InstanceOf {
 
@@ -21,5 +22,8 @@ public class InstanceOf {
 
         assertThat(object).as("foo").isInstanceOf(Boolean.class).as("bar").isInstanceOf(Boolean.class);
         assertThat(object instanceof Boolean).as("foo").isEqualTo(Boolean.TRUE).as("bar").isEqualTo(false);
+
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/InstanceOf/InstanceOfBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class InstanceOf {
 
@@ -21,5 +22,8 @@ public class InstanceOf {
 
         assertThat(object instanceof Boolean).as("foo").isEqualTo(Boolean.TRUE).as("bar").isEqualTo(true);
         assertThat(object instanceof Boolean).as("foo").isEqualTo(Boolean.TRUE).as("bar").isEqualTo(false);
+
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/InvertedBooleanCondition/InvertedBooleanConditionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class InvertedBooleanCondition {
 
@@ -35,5 +36,8 @@ public class InvertedBooleanCondition {
 
         assertThat(primitive).as("foo").isFalse().as("bar").isFalse();
         assertThat(primitive).as("foo").isFalse().as("bar").isTrue();
+
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/InvertedBooleanCondition/InvertedBooleanConditionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class InvertedBooleanCondition {
 
@@ -35,5 +36,8 @@ public class InvertedBooleanCondition {
 
         assertThat(!primitive).as("foo").isEqualTo(Boolean.TRUE).as("bar").isNotEqualTo(false);
         assertThat(!primitive).as("foo").isEqualTo(Boolean.TRUE).as("bar").isNotEqualTo(true);
+
+        org.junit.Assert.assertThat(object, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/Java8Optional/Java8OptionalAfter.java

@@ -1,6 +1,7 @@
 import java.util.Optional;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class Java8Optional {
 
@@ -29,8 +30,21 @@ public class Java8Optional {
         assertThat(opt).isPresent();
         assertThat(opt).isPresent();
 
+        //assertThat(opt.get()).isEqualTo(opt.get()); // there's a better version than contains(opt.get())
+        assertThat(opt.orElse(null)).isEqualTo(opt.get());
+        //assertThat(opt.get()).isEqualTo(opt.orElse(null)); // there's a better version than contains(opt.orElse(null))
+
+        assertThat(opt).contains(opt.get());
+        assertThat(opt).contains(opt.orElse(null));
+
+        String possibleNullString = System.getProperty("username");
+        String notNullString = "Narf";
+
         assertThat(opt).as("foo").contains("foo");
         assertThat(opt).contains("foo");
+        assertThat(opt).isEqualTo(Optional.ofNullable(null));
+        assertThat(opt).isEqualTo(Optional.ofNullable(possibleNullString));
+        assertThat(opt).isEqualTo(Optional.ofNullable(notNullString));
         assertThat(opt).isNotEqualTo(Optional.of("foo"));
         assertThat(opt).isNotEqualTo(Optional.ofNullable("foo"));
 
@@ -43,5 +57,10 @@ public class Java8Optional {
         assertThat(opt.get()).isEqualTo("foo").isSameAs("foo").isNotEqualTo("foo").isNotSameAs("foo");
 
         assertThat(opt.orElse("foo")).as("foo").isEqualTo(null);
+
+        assertThat(opt.orElse(null)).as("foo").isEqualTo(null).isNotNull();
+
+        org.junit.Assert.assertThat(opt, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/Java8Optional/Java8OptionalBefore.java

@@ -1,6 +1,7 @@
 import java.util.Optional;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class Java8Optional {
 
@@ -29,8 +30,21 @@ public class Java8Optional {
         assertThat(opt.orElse(null)).isNotEqualTo(null);
         assertThat(opt.orElse(null)).isNotNull();
 
+        //assertThat(opt.get()).isEqualTo(opt.get()); // there's a better version than contains(opt.get())
+        assertThat(opt.orElse(null)).isEqualTo(opt.get());
+        //assertThat(opt.get()).isEqualTo(opt.orElse(null)); // there's a better version than contains(opt.orElse(null))
+
+        assertThat(opt).contains(opt.get());
+        assertThat(opt).contains(opt.orElse(null));
+
+        String possibleNullString = System.getProperty("username");
+        String notNullString = "Narf";
+
         assertThat(opt).as("foo").isEqualTo(Optional.of("foo"));
         assertThat(opt).isEqualTo(Optional.ofNullable("foo"));
+        assertThat(opt).isEqualTo(Optional.ofNullable(null));
+        assertThat(opt).isEqualTo(Optional.ofNullable(possibleNullString));
+        assertThat(opt).isEqualTo(Optional.ofNullable(notNullString));
         assertThat(opt).isNotEqualTo(Optional.of("foo"));
         assertThat(opt).isNotEqualTo(Optional.ofNullable("foo"));
 
@@ -43,5 +57,10 @@ public class Java8Optional {
         assertThat(opt.get()).isEqualTo("foo").isSameAs("foo").isNotEqualTo("foo").isNotSameAs("foo");
 
         assertThat(opt.orElse("foo")).as("foo").isEqualTo(null);
+
+        assertThat(opt.orElse(null)).as("foo").isEqualTo(null).isNotNull();
+
+        org.junit.Assert.assertThat(opt, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/JoinStatements/JoinStatementsAfter.java

@@ -1,6 +1,7 @@
 import java.util.*;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class JoinStatements {
 
@@ -24,21 +25,28 @@ public class JoinStatements {
                 .doesNotContain("foobar");
 
         assertThat("narf").isNotEqualTo("puit");
-        assertThat(list).as("bar").contains("barbar").as("foo").hasSize(2);
+        assertThat(list).as("bar").contains("barbar")
+                .as("foo").hasSize(2);
         assertThat(list).as("evil").extracting(String::length).contains(2);
 
         assertThat(list).as("bar").contains("barbar");
         assertThat(otherList).contains("puit");
         assertThat(list).as("foo").hasSize(2);
         if (true) {
-            assertThat(list).doesNotContain("narf").as("bar").contains("barbar");
+            assertThat(list).doesNotContain("narf")
+                    .as("bar").contains("barbar");
         }
-        assertThat(list.get(0)).isNotEmpty().hasSize(3).isEqualTo("bar");
+        assertThat(list.get(0)).isNotEmpty()
+                .hasSize(3)
+                .isEqualTo("bar");
 
         assertThat(otherList.get(0)).isNotEmpty();
         assertThat(list.get(0)).hasSize(3);
 
-        assertThat(list.get(0) + "foo").isEqualTo("bar").doesNotStartWith("foo");
+        assertThat(list.get(0) + "foo").isNotNull()
+                // hey, a comment mixed with line breaks due to too many joins
+                .isEqualTo("bar")
+                .doesNotStartWith("foo");
 
         assertThat(otherList.get(0) + "foo").isEqualTo("bar");
         assertThat(list.get(0) + "foo").doesNotStartWith("foo");
@@ -57,5 +65,8 @@ public class JoinStatements {
         assertThat(list.get(i++).toLowerCase()).isEqualTo("foo");
         assertThat(list.get(--i)).isEqualTo("foo");
         assertThat(list.get(--i)).isEqualTo("foo");
+
+        org.junit.Assert.assertThat(list, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/JoinStatements/JoinStatementsBefore.java

@@ -1,6 +1,7 @@
 import java.util.*;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class JoinStatements {
 
@@ -39,6 +40,8 @@ public class JoinStatements {
         assertThat(otherList.get(0)).isNotEmpty();
         assertThat(list.get(0)).hasSize(3);
 
+        assertThat(list.get(0) + "foo").isNotNull();
+        // hey, a comment mixed with line breaks due to too many joins
         assertThat(list.get(0) + "foo").isEqualTo("bar");
         assertThat(list.get(0) + "foo").doesNotStartWith("foo");
 
@@ -59,5 +62,8 @@ public class JoinStatements {
         assertThat(list.get(i++).toLowerCase()).isEqualTo("foo");
         assertThat(list.get(--i)).isEqualTo("foo");
         assertThat(list.get(--i)).isEqualTo("foo");
+
+        org.junit.Assert.assertThat(list, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/JoinVarArgsContains/JoinVarArgsContainsAfter.java

@@ -0,0 +1,22 @@
+import java.util.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+
+public class JoinVarArgsContains {
+
+    private void joinVarArgsContains() {
+        List<String> list = new ArrayList<>();
+
+        assertThat(list).contains("foo", "bar", "etc").hasSize(2);
+        assertThat(list).contains("foo").as("narf").contains("bar");
+        assertThat(list).doesNotContain("foo", "bar");
+        assertThat(list).containsOnlyOnce("foo", "etc") // will we lose this comment?
+                .hasSize(2).contains("bar", "narf", "1", "2", "3").doesNotContain("puit", "Jens Stoltenberg is a war-monger", "and an atomic playboy") /* inline */; // the final comment
+
+        assertThat(list).contains("foo").doesNotContain("bar").containsOnlyOnce("narf");
+
+        org.junit.Assert.assertThat(list, null);
+        fail("oh no!");
+    }
+}

src/test/resources/inspections/JoinVarArgsContains/JoinVarArgsContainsBefore.java

@@ -0,0 +1,28 @@
+import java.util.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+
+public class JoinVarArgsContains {
+
+    private void joinVarArgsContains() {
+        List<String> list = new ArrayList<>();
+
+        assertThat(list).contains("foo").contains(/* foo */ "bar" /* bar */).hasSize(2).contains("etc");
+        assertThat(list).contains("foo").as("narf").contains("bar");
+        assertThat(list).doesNotContain("foo").doesNotContain("bar");
+        assertThat(list).containsOnlyOnce()
+                .containsOnlyOnce("foo") // will we lose this comment?
+                .hasSize(2) // this is part of the contains("bar")
+                .contains("bar").containsOnlyOnce("etc") /* where does this go? */
+                .contains("narf") // what about this one?
+                .doesNotContain("puit", "Jens Stoltenberg is a war-monger")
+                .doesNotContain("and an atomic playboy")
+                .contains("1", "2", "3") /* inline */; // the final comment
+
+        assertThat(list).contains("foo").doesNotContain("bar").containsOnlyOnce("narf");
+
+        org.junit.Assert.assertThat(list, null);
+        fail("oh no!");
+    }
+}

src/test/resources/inspections/ObjectExpression/ObjectExpressionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class ObjectExpression {
 
@@ -23,5 +24,8 @@ public class ObjectExpression {
         assertThat(object.equals(otherObject)).isEqualTo(foo);
 
         assertThat(object).as("doh!").isEqualTo(otherObject).isEqualTo(otherObject);
+
+        org.junit.Assert.assertThat(foo, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/ObjectExpression/ObjectExpressionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class ObjectExpression {
 
@@ -23,5 +24,8 @@ public class ObjectExpression {
         assertThat(object.equals(otherObject)).isEqualTo(foo);
 
         assertThat(object.equals(otherObject)).as("doh!").isTrue().isEqualTo(true);
+
+        org.junit.Assert.assertThat(foo, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/ObjectIsNullOrNotNull/ObjectIsNullOrNotNullAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class ObjectIsNull {
 
@@ -13,5 +14,8 @@ public class ObjectIsNull {
 
         assertThat(new Object()).as("foo").isNotNull().as("bar").isEqualTo(new Object()).as("etc").isNull();
         assertThat(new Object()).as("foo").isEqualTo(null).as("bar").isEqualTo(new Object()).as("etc").isNotNull();
+
+        org.junit.Assert.assertThat("foo", null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/ObjectIsNullOrNotNull/ObjectIsNullOrNotNullBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class ObjectIsNull {
 
@@ -13,5 +14,8 @@ public class ObjectIsNull {
 
         assertThat(new Object()).as("foo").isNotEqualTo(null).as("bar").isEqualTo(new Object()).as("etc").isEqualTo(null);
         assertThat(new Object()).as("foo").isEqualTo(null).as("bar").isEqualTo(new Object()).as("etc").isNotEqualTo(null);
+
+        org.junit.Assert.assertThat("foo", null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/Size/SizeAfter.java

@@ -1,6 +1,7 @@
 import java.util.ArrayList;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class Size {
 
@@ -99,5 +100,12 @@ public class Size {
         assertThat(stringBuilder.length()).as("foo").isEqualTo(0).isZero().as("bar").isNotZero().isEqualTo(10);
 
         assertThat(stringBuilder).as("foo").isNotEmpty().hasSize(2).as("bar").hasSameSizeAs(otherList).hasSameSizeAs(array);
+
+        int foo = 1;
+        assertThat(foo).isEqualTo(0);
+        assertThat(string.length()).isPositive();
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/Size/SizeBefore.java

@@ -1,6 +1,7 @@
 import java.util.ArrayList;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class Size {
 
@@ -99,5 +100,12 @@ public class Size {
         assertThat(stringBuilder.length()).as("foo").isEqualTo(0).isZero().as("bar").isNotZero().isEqualTo(10);
 
         assertThat(stringBuilder).as("foo").isNotEmpty().hasSize(2).as("bar").hasSize(otherList.size()).hasSize(array.length);
+
+        int foo = 1;
+        assertThat(foo).isEqualTo(0);
+        assertThat(string.length()).isPositive();
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/StringExpression/StringExpressionAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class StringExpression {
 
@@ -49,5 +50,8 @@ public class StringExpression {
         assertThat(string).as("foo").doesNotEndWith("foo").as("bar").doesNotEndWith("foo");
         assertThat(string.endsWith("foo")).as("foo").isEqualTo(false).as("bar").isTrue();
         assertThat(string.endsWith("foo")).as("foo").satisfies(it -> it.booleanValue()).as("bar").isFalse();
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/StringExpression/StringExpressionBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class StringExpression {
 
@@ -49,5 +50,8 @@ public class StringExpression {
         assertThat(string.endsWith("foo")).as("foo").isEqualTo(false).as("bar").isFalse();
         assertThat(string.endsWith("foo")).as("foo").isEqualTo(false).as("bar").isTrue();
         assertThat(string.endsWith("foo")).as("foo").satisfies(it -> it.booleanValue()).as("bar").isFalse();
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/StringIsEmpty/StringIsEmptyAfter.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class StringIsEmpty {
 
@@ -18,5 +19,8 @@ public class StringIsEmpty {
 
         assertThat(string).as("foo").isEqualTo("").as("bar").hasSize(0).hasSameSizeAs("foo").isEmpty();
         assertThat(string).as("foo").isEqualTo("").as("bar").hasSize(0).hasSameSizeAs("foo").isEmpty();
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/inspections/StringIsEmpty/StringIsEmptyBefore.java

@@ -1,4 +1,5 @@
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 public class StringIsEmpty {
 
@@ -18,5 +19,8 @@ public class StringIsEmpty {
 
         assertThat(string).as("foo").isEqualTo("").as("bar").hasSize(0).hasSameSizeAs("foo").isEqualTo("");
         assertThat(string).as("foo").isEqualTo("").as("bar").hasSize(0).hasSameSizeAs("foo").hasSize(0);
+
+        org.junit.Assert.assertThat(string, null);
+        fail("oh no!");
     }
 }

src/test/resources/references/FindReference11.java

@@ -0,0 +1,15 @@
+import org.assertj.core.extractor.Extractors;
+
+import java.util.Collections;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class FindReference10 {
+
+    private void findReferences() {
+        List<Contact> contactList = Collections.emptyList();
+
+        assertThat(contactList).extracting("narf<caret>").isEqualTo("foo");
+    }
+}