@Override
    public V getOrDefault(Object key, V defaultValue) {
        return underlying().getOrDefault(key, defaultValue);
    }
@Test
    public void testDelegationOfGetOrDefault() {
        new PCollectionsHashMapWrapperDelegationChecker<>()
            .defineMockConfigurationForFunctionInvocation(mock -> mock.getOrDefault(eq(this), eq(this)), this)
            .defineWrapperFunctionInvocationAndMockReturnValueTransformation(wrapper -> wrapper.getOrDefault(this, this), identity())
            .doFunctionDelegationCheck();
    }