#35 Making @WithClasses usable on the method level

processor/src/test/java/org/mapstruct/ap/testutil/IssueKey.java

@@ -29,5 +29,11 @@ import java.lang.annotation.RetentionPolicy;
  */
 @Retention(RetentionPolicy.SOURCE)
 public @interface IssueKey {
+
+    /**
+     * The issue number.
+     *
+     * @return the issue number
+     */
     String value();
 }

processor/src/test/java/org/mapstruct/ap/testutil/MapperTestBase.java

@@ -45,9 +45,8 @@ import org.testng.annotations.BeforeMethod;
 import static org.fest.assertions.Assertions.assertThat;
 
 /**
- * Base class for all mapper tests. Sub-classes must implement
+ * Base class for all mapper tests. The classes to be compiled for a given test
- * {@link #getTestClasses()} to return the classes to be compiled for a given
+ * method must be specified via {@link WithClasses}.
- * test.
  *
  * @author Gunnar Morling
  */
@@ -95,7 +94,7 @@ public abstract class MapperTestBase {
     @BeforeMethod
     public void generateMapperImplementation(Method testMethod) {
         diagnostics = new DiagnosticCollector<JavaFileObject>();
-        List<File> sourceFiles = getSourceFiles( getTestClasses() );
+        List<File> sourceFiles = getSourceFiles( getTestClasses( testMethod ) );
 
         boolean compilationSuccessful = compile( diagnostics, sourceFiles );
 
@@ -125,11 +124,24 @@ public abstract class MapperTestBase {
     /**
      * Returns the classes to be compiled for this test.
      *
+     * @param testMethod The test method of interest
+     *
      * @return A list containing the classes to be compiled for this test
      */
-    private List<Class<?>> getTestClasses() {
+    private List<Class<?>> getTestClasses(Method testMethod) {
-        WithClasses withClasses = this.getClass().getAnnotation( WithClasses.class );
+        WithClasses withClasses = testMethod.getAnnotation( WithClasses.class );
-        return withClasses != null ? Arrays.asList( withClasses.value() ) : Collections.<Class<?>>emptyList();
+
+        if ( withClasses == null ) {
+            withClasses = this.getClass().getAnnotation( WithClasses.class );
+        }
+
+        if ( withClasses == null || withClasses.value().length == 0 ) {
+            throw new IllegalStateException(
+                "The classes to be compiled during the test must be specified via @WithClasses."
+            );
+        }
+
+        return Arrays.asList( withClasses.value() );
     }
 
     private List<File> getSourceFiles(List<Class<?>> classes) {

processor/src/test/java/org/mapstruct/ap/testutil/WithClasses.java

@@ -18,13 +18,20 @@
  */
 package org.mapstruct.ap.testutil;
 
+import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
 
 /**
+ * Specifies the classes to compile during an annotation processor test. If
+ * given both on the class-level and the method-level for a given test, the
+ * settings on the method take precedence.
+ *
  * @author Gunnar Morling
  */
 @Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE, ElementType.METHOD })
 public @interface WithClasses {
     Class<?>[] value();
 }