Review: Simplify test and add some comments as to why synthetic / bri…

…dge members are created in the example class

Signed-off-by: Peter Gafert <peter.gafert@tngtech.com>

archunit/src/test/java/com/tngtech/archunit/core/importer/ClassFileImporterTest.java

@@ -391,14 +391,14 @@ public void handles_static_modifier_of_nested_classes() throws Exception {
     public void handles_synthetic_modifiers() throws Exception {
         JavaClasses classes = classesIn("testexamples/syntheticimport").classes;
 
-        assertThat(classes.get(ClassWithSynthetics.ClassWithSyntheticField.class).getFields().size()).isEqualTo(1);
-        assertThat(classes.get(ClassWithSynthetics.ClassWithSyntheticField.class).getFields().toArray(new JavaField[]{})[0].getModifiers()).as("modifiers of field in ClassWithSynthetics.ClassWithSyntheticField").contains(SYNTHETIC);
+        JavaField syntheticField = getOnlyElement(classes.get(ClassWithSynthetics.ClassWithSyntheticField.class).getFields());
+        assertThat(syntheticField.getModifiers()).as("modifiers of field in ClassWithSynthetics.ClassWithSyntheticField").contains(SYNTHETIC);
 
-        assertThat(classes.get(ClassWithSynthetics.ClassWithSyntheticMethod.class).getMethods().size()).isEqualTo(1);
-        assertThat(classes.get(ClassWithSynthetics.ClassWithSyntheticMethod.class).getMethods().toArray(new JavaMethod[]{})[0].getModifiers()).as("modifiers of method in ClassWithSynthetics.ClassWithSyntheticMethod").contains(SYNTHETIC);
+        JavaMethod syntheticMethod = getOnlyElement(classes.get(ClassWithSynthetics.ClassWithSyntheticMethod.class).getMethods());
+        assertThat(syntheticMethod.getModifiers()).as("modifiers of method in ClassWithSynthetics.ClassWithSyntheticMethod").contains(SYNTHETIC);
 
-        assertThat(classes.get(ClassWithSynthetics.class).getMethod("compare", Object.class, Object.class).getModifiers()).as("modifiers of bridge method in ClassWithSynthetics").contains(BRIDGE);
-        assertThat(classes.get(ClassWithSynthetics.class).getMethod("compare", Object.class, Object.class).getModifiers()).as("modifiers of bridge method in ClassWithSynthetics").contains(SYNTHETIC);
+        JavaMethod compareMethod = classes.get(ClassWithSynthetics.class).getMethod("compare", Object.class, Object.class);
+        assertThat(compareMethod.getModifiers()).as("modifiers of bridge method in ClassWithSynthetics").contains(BRIDGE, SYNTHETIC);
     }
 
     @Test

archunit/src/test/java/com/tngtech/archunit/core/importer/testexamples/syntheticimport/ClassWithSynthetics.java

@@ -2,10 +2,14 @@
 
 import java.util.Comparator;
 
+@SuppressWarnings({"unused", "InnerClassMayBeStatic"})
 public class ClassWithSynthetics implements Comparator<String> {
+    // for (non-static) inner classes the compiler must create a synthetic field, holding a reference to the outer class
     public class ClassWithSyntheticField {
     }
 
+    // for accesses to private fields of inner classes, the compiler must create a synthetic method to allow access to this field
+    // thus together with the method 'getNestedField', this causes the existence of a synthetic method
     public class ClassWithSyntheticMethod {
         private String nestedField;
     }
@@ -14,6 +18,7 @@ public String getNestedField() {
         return new ClassWithSyntheticMethod().nestedField;
     }
 
+    // to cover type erasure, the compiler must add a bridge method with signature compare(Object, Object) here
     @Override
     public int compare(String o1, String o2) {
         return 0;