Added a first version of a new inspection that tries to detect bogus uses of return statements in test methods and replaces them by assumeThat() calls. Removed oraclejdk8 from travis-ci. Added custom Jupiter DisplayNameGenerator for user friendly test names in report. Extended documentation. Removed Playground.

src/test/resources/inspections/AssumeThat/AssumeThatBefore.java

@@ -0,0 +1,156 @@
+import org.junit.Test;
+
+import java.util.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class AssumeThat {
+
+    @Test
+    public void junit4_return_very_early() {
+        if (new Random().nextBoolean()) {
+            return;
+        } else System.out.println("sweet!"); // single else statement
+        String foobar = System.getProperty("foobar");
+        assertThat(foobar).isNotEmpty();
+    }
+
+    @Test
+    public void junit4_return_in_else_branch_with_declaration_in_code_block_and_lots_of_comments() {
+        // primary comments
+        if (new Random().nextBoolean()) /* strange place for a comment */ {
+            // Block start comment will be retained
+            String anotherString = "narf"; // This one is likely to be kept
+            assertThat(foobar).isNotEmpty();
+            assertThat(foobar).isEqualTo(anotherString);
+            // Block end comment is also going to be retained
+        } /* weird places */ else /* more weird places */ { // this one is lost
+            return; // Would be sweet to keep this comment, too.
+        } // another comment lost
+        // well, well, let's do some checks
+        String foobar = System.getProperty("foobar");
+        assertThat(foobar).isNotEmpty();
+    }
+
+    @org.junit.jupiter.api.Test
+    public void junit5_return_after_call_without_else_branch() {
+        String foobar = System.getProperty("car_manufacturer");
+        if (foobar.equals("Volkswagen")) return; // no need for Volkswagen to perform tests
+        assertThat(foobar).isNotEmpty();
+    }
+
+    @org.junit.jupiter.api.TestTemplate
+    public void junit5_return_inside_recursion_with_comments() {
+        String foobar = System.getProperty("car_manufacturer");
+        if (foobar != null) {
+            if (!foobar.equals("Volkswagen")) {
+                // I doubted this comment will be retained -- but surprise!
+                assertThat(foobar).isNotEmpty();
+                // we might keep this one alright.
+                foobar = "narf";
+                // And the final one? Again what learned.
+            } else {
+                // ooops, how did that happen?
+                return;
+            }
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+        if(foobar.length() == 0)
+        {
+            return;
+        }
+        assertThat(foobar).endsWith("!!!");
+    }
+
+    @Test
+    public void junit4_return_after_assertion() {
+        String foobar = System.getProperty("car_manufacturer");
+        assertThat(foobar).isNotNull();
+        if (!foobar.equals("Volkswagen")) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            return;
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+    }
+
+    @Test
+    public void junit4_return_after_assertions_in_subroutine() {
+        String foobar = System.getProperty("car_manufacturer");
+        assertStuff(foobar);
+        if (!foobar.equals("Volkswagen")) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            return;
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+    }
+
+    @Test
+    public void junit4_return_after_assertions_in_deep_subroutine() {
+        String foobar = System.getProperty("car_manufacturer");
+        firstMethod();
+        if (!foobar.equals("Volkswagen")) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            return;
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+    }
+
+    @Test
+    public void junit4_return_after_assertions_in_deep_subroutine_with_recursion() {
+        String foobar = System.getProperty("car_manufacturer");
+        firstMethodWithPotentialRecursion();
+        if (!foobar.equals("Volkswagen")) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            return;
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+    }
+
+    @Test
+    public void junit4_no_harm_with_infinite_recursion() {
+        String foobar = System.getProperty("car_manufacturer");
+        infiniteRecursion();
+        if (!foobar.equals("Volkswagen")) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            return;
+        }
+        assertThat(foobar).startsWith("another ecology rapist");
+    }
+
+    private void assertStuff(String foobar) {
+        if (new Random().nextBoolean()) {
+            assertThat(foobar).isNotEmpty();
+        } else {
+            assertThat(foobar).isNull();
+        }
+    }
+
+    private void firstMethod() {
+        if (new Random().nextBoolean()) {
+            assertStuff("narf");
+        }
+    }
+
+    private void firstMethodWithPotentialRecursion() {
+        if (new Random().nextBoolean()) {
+            assertStuff("narf");
+        } else {
+            infiniteRecursion();
+        }
+    }
+
+    private void infiniteRecursion() {
+        secondaryRecursion();
+        secondaryRecursion();
+    }
+
+    private void secondaryRecursion() {
+        infiniteRecursion();
+        infiniteRecursion();
+    }
+}