### Question:
NestedMappingSupport { boolean hasOngoingMapping(ResourceModelMetaData metadata) { if (metadata == null) { throw new IllegalArgumentException("Method argument metadata must not be null"); } return this.mappingStack.get().contains(metadata); }  void beginRecordingMappings(); @CheckForNull Map<Object, Mapping<?>> getRecordedMappings(); void endRecordingMappings();  }### Answer:
@Test(expected = IllegalArgumentException.class) public void testCheckingForResourceModelMappingDoesNotAcceptNull() { this.testee.hasOngoingMapping(null); }