### Question:
ItemDefinition extends NamedElement implements HasTypeRef,
                                                            DynamicReadOnly { @Override public List<HasTypeRef> getHasTypeRefs() { return new ArrayList<>(singletonList(this)); } ItemDefinition();  ItemDefinition(final Id id,
                          final Description description,
                          final Name name,
                          final QName typeRef,
                          final UnaryTests allowedValues,
                          final List<ItemDefinition> itemComponent,
                          final String typeLanguage,
                          final Boolean isCollection,
                          final Boolean allowOnlyVisualChange); @Override QName getTypeRef(); @Override void setTypeRef(final QName value); @Override DMNModelInstrumentedBase asDMNModelInstrumentedBase(); @Override List<HasTypeRef> getHasTypeRefs(); UnaryTests getAllowedValues(); void setAllowedValues(final UnaryTests value); List<ItemDefinition> getItemComponent(); String getTypeLanguage(); void setTypeLanguage(final String value); boolean isIsCollection(); void setIsCollection(final Boolean value); boolean isImported(); @Override boolean equals(final Object o); @Override int hashCode(); @Override void setAllowOnlyVisualChange(final boolean allowOnlyVisualChange); @Override boolean isAllowOnlyVisualChange();  }### Answer:
@Test public void testGetHasTypeRefs() { final List<HasTypeRef> actualHasTypeRefs = itemDefinition.getHasTypeRefs(); final List<HasTypeRef> expectedHasTypeRefs = singletonList(itemDefinition); assertEquals(expectedHasTypeRefs, actualHasTypeRefs); }