### Question:
ObjectAssociationAbstract extends ObjectMemberAbstract implements ObjectAssociation { @Override public boolean isMandatory() { return MandatoryFacet.isMandatory(this); } ObjectAssociationAbstract(
            final FacetedMethod facetedMethod,
            final FeatureType featureType,
            final ObjectSpecification specification); @Override FacetHolder getFacetHolder(); @Override ObjectSpecification getOnType(); @Override ObjectSpecification getSpecification(); @Override boolean isNotPersisted(); @Override boolean hasChoices(); @Override boolean isMandatory(); @Override abstract boolean isEmpty(final ManagedObject adapter, final InteractionInitiatedBy interactionInitiatedBy); @Override boolean isOneToOneAssociation();  }### Answer:
@Test public void optional() throws Exception { assertFalse(objectAssociation.isMandatory()); }
@Test public void mandatory() throws Exception { final MandatoryFacet mockFacet = mockFacetIgnoring(MandatoryFacet.class); facetedMethod.addFacet(mockFacet); assertTrue(objectAssociation.isMandatory()); }