#187 adding unit test to make sure that reverse mapping also works for source constants

processor/src/test/java/org/mapstruct/ap/test/sourceconstants/SourceConstantsTest.java

@@ -64,6 +64,24 @@ public class SourceConstantsTest {
         assertThat( target.getNameConstants() ).isEqualTo( Arrays.asList( "jack", "jill", "tom" ) );
     }
 
+    @Test
+    @IssueKey( "187" )
+    @WithClasses( {
+        Source.class,
+        Target.class,
+        SourceTargetMapper.class,
+        StringListMapper.class
+    } )
+    public void shouldMapTargetToSourceWithoutWhining() throws ParseException {
+        Target target = new Target();
+        target.setPropertyThatShouldBeMapped( "SomeProperty" );
+
+        Source source = SourceTargetMapper.INSTANCE.targetToSource( target );
+
+        assertThat( source ).isNotNull();
+        assertThat( target.getPropertyThatShouldBeMapped() ).isEqualTo( "SomeProperty" );
+    }
+
     @Test
     @IssueKey( "187" )
     @WithClasses( {

processor/src/test/java/org/mapstruct/ap/test/sourceconstants/SourceTargetMapper.java

@@ -40,4 +40,5 @@ public interface SourceTargetMapper {
         @Mapping( target = "nameConstants", expression = "jack-jill-tom" )
     } )
     Target sourceToTarget(Source s);
+    Source targetToSource(Target t);
 }