### Question:
Expression extends DMNElement implements HasTypeRef,
                                                               HasComponentWidths { @Override public java.util.List<Double> getComponentWidths() { final int requiredComponentWidthCount = getRequiredComponentWidthCount(); if (componentWidths.size() != requiredComponentWidthCount) { componentWidths = new ArrayList<>(requiredComponentWidthCount); IntStream.range(0, requiredComponentWidthCount).forEach(i -> componentWidths.add(null)); } return componentWidths; } Expression();  Expression(final Id id,
                      final Description description,
                      final QName typeRef); abstract Expression copy(); @Override QName getTypeRef(); @Override void setTypeRef(final QName typeRef); @Override java.util.List<Double> getComponentWidths(); @Override DMNModelInstrumentedBase asDMNModelInstrumentedBase(); @Override List<HasTypeRef> getHasTypeRefs();  }### Answer:
@Test public void testComponentWidths() { assertEquals(expression.getRequiredComponentWidthCount(), expression.getComponentWidths().size()); expression.getComponentWidths().forEach(Assert::assertNull); }