Implemented AssertThatEnumerableIsEmptyInspection. Improved literal values by constant value calculation, more refactoring.

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

@@ -0,0 +1,18 @@
+import java.util.ArrayList;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EnumerableIsEmpty {
+
+    private void enumerableIsEmpty() {
+        assertThat("string").as("foo").isEmpty();
+        assertThat(new StringBuilder()).as("bar").isEmpty();
+        assertThat(new ArrayList<Long>()).as("etc").isEmpty();
+        assertThat(new Long[1]).as("etc").isEmpty();
+
+        assertThat("string").as("foo").hasSize(1);
+        assertThat(new StringBuilder()).as("bar").hasSize(1);
+        assertThat(new ArrayList<Long>()).as("etc").hasSize(1);
+        assertThat(new Long[1]).as("etc").hasSize(1);
+    }
+}

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

@@ -0,0 +1,18 @@
+import java.util.ArrayList;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EnumerableIsEmpty {
+
+    private void enumerableIsEmpty() {
+        assertThat("string").as("foo").hasSize(0);
+        assertThat(new StringBuilder()).as("bar").hasSize(0 + 0);
+        assertThat(new ArrayList<Long>()).as("etc").hasSize(10 / 100);
+        assertThat(new Long[1]).as("etc").hasSize(1 - 1);
+
+        assertThat("string").as("foo").hasSize(1);
+        assertThat(new StringBuilder()).as("bar").hasSize(1);
+        assertThat(new ArrayList<Long>()).as("etc").hasSize(1);
+        assertThat(new Long[1]).as("etc").hasSize(1);
+    }
+}

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

@@ -11,7 +11,7 @@ public class StringIsEmpty {
         assertThat(string).as("bar").hasSize(0);
 
         assertThat(stringBuilder).isEqualTo("foo");
-        assertThat(stringBuilder).as("foo").isEqualTo("");
+        assertThat(stringBuilder).as("foo").isEqualTo("" + "");
         assertThat(stringBuilder).as("bar").hasSize(0);
 
         assertThat(new Object()).isEqualTo("");