diff --git a/src/test/java/spoon/test/parent/ParentContractTest.java b/src/test/java/spoon/test/parent/ParentContractTest.java
index b55211a274a..52aba43afa3 100644
--- a/src/test/java/spoon/test/parent/ParentContractTest.java
+++ b/src/test/java/spoon/test/parent/ParentContractTest.java
@@ -11,12 +11,14 @@
 import spoon.reflect.code.CtTypeAccess;
 import spoon.reflect.declaration.CtAnnotationType;
 import spoon.reflect.declaration.CtElement;
+import spoon.reflect.declaration.CtPackage;
 import spoon.reflect.declaration.CtType;
 import spoon.reflect.factory.CoreFactory;
 import spoon.reflect.factory.Factory;
 import spoon.reflect.reference.CtActualTypeContainer;
 import spoon.reflect.reference.CtReference;
 import spoon.reflect.visitor.CtVisitable;
+import spoon.test.SpoonTestHelpers;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -26,6 +28,8 @@
 import java.util.List;
 import java.util.Queue;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static spoon.testing.utils.ModelUtils.createFactory;
@@ -35,17 +39,14 @@
 public class ParentContractTest<T extends CtVisitable> {
 
 	private static Factory factory = createFactory();
+	private static final List<CtType<? extends CtElement>> allInstantiableMetamodelInterfaces = SpoonTestHelpers.getAllInstantiableMetamodelInterfaces();
 
 	@Parameterized.Parameters(name = "{0}")
 	public static Collection<Object[]> data() throws Exception {
 		List<Object[]> values = new ArrayList<>();
-		for (Method method : CoreFactory.class.getDeclaredMethods()) {
-			if (method.getName().startsWith("create")
-					&& method.getParameterCount() == 0
-					&& method.getReturnType().getSimpleName().startsWith("Ct")
-					&& !CtReference.class.isAssignableFrom(method.getReturnType())
-					){
-				values.add(new Object[] { method.getReturnType(), method.invoke(factory.Core()) });
+		for (CtType t : allInstantiableMetamodelInterfaces) {
+			if (!(CtReference.class.isAssignableFrom(t.getActualClass()))) {
+				values.add(new Object[] { t.getActualClass(), factory.Core().create(t.getActualClass()) });
 			}
 		}
 		return values;
@@ -72,7 +73,7 @@ private List<Method> getMethodsToInvoke(Class<?> entry) throws Exception {
 		while (!tocheck.isEmpty()) {
 			Class<?> intf = tocheck.poll();
 
-			Assert.assertTrue(intf.isInterface());
+			assertTrue(intf.isInterface());
 			if (!intf.getSimpleName().startsWith("Ct")) {
 				continue;
 			}
@@ -101,10 +102,20 @@ private List<Method> getMethodsToInvoke(Class<?> entry) throws Exception {
 		return toInvoke;
 	}
 
+	private CtElement createCompatibleObject(Class c) {
+		for(CtType t : allInstantiableMetamodelInterfaces) {
+			if (c.isAssignableFrom(t.getActualClass())) {
+				return factory.Core().create(t.getActualClass());
+			}
+		}
+		throw new IllegalArgumentException();
+	}
 	@Test
 	public void testContract() throws Throwable {
+		// contract: all setters/adders must set the parent (not necessarily the direct parent, can be upper in the parent tree, for instance when injecting blocks
 		Object o = instance;
-		for (Method setter : getMethodsToInvoke(toTest)) {
+		List<Method> methodsToInvoke = getMethodsToInvoke(toTest);
+		for (Method setter : methodsToInvoke) {
 
 			// special case: impossible methods on some objects (they throw an UnsupportedOperationException)
 			if (setter.getAnnotation(Deprecated.class) != null) continue;
@@ -118,14 +129,20 @@ public void testContract() throws Throwable {
 			if (o instanceof CtTypeAccess && "setType".equals(setter.getName())) continue;
 			if (o instanceof CtType && "setSuperclass".equals(setter.getName())) continue;
 
-			CtElement mockedArgument = (CtElement) mock(setter.getParameters()[0].getType(),  Mockito.withSettings().extraInterfaces(Comparable.class));
+
+			CtElement argument = createCompatibleObject((Class<? extends CtElement>) setter.getParameters()[0].getType());
+			// an empty package is merged with the existing one
+			// we have to give it a name
+			if (argument instanceof CtPackage) {
+				((CtPackage)argument).setSimpleName("foobar");
+			}
 			try {
 				// we create a fresh object
 				CtElement receiver = ((CtElement) o).clone();
 				// we invoke the setter
-				setter.invoke(receiver, new Object[] { mockedArgument });
+				setter.invoke(receiver, new Object[] { argument });
 				// we check that setParent has been called
-				verify(mockedArgument).setParent((CtElement) receiver);
+				assertTrue(argument.hasParent(receiver));
 			} catch (AssertionError e) {
 				Assert.fail("call setParent contract failed for " + setter.toString() + " " + e.toString());
 			} catch (InvocationTargetException e) {