@Override
    public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
        // will throw UnsupportedOperationException; delegate anyway for testability
        underlying().replaceAll(function);
    }
@Test
    public void testDelegationOfUnsupportedFunctionReplaceAll() {
        final BiFunction<Object, Object, Object> mockBiFunction = mock(BiFunction.class);
        new PCollectionsHashMapWrapperDelegationChecker<>()
            .defineMockConfigurationForVoidMethodInvocation(mock -> mock.replaceAll(eq(mockBiFunction)))
            .defineWrapperVoidMethodInvocation(wrapper -> wrapper.replaceAll(mockBiFunction))
            .doUnsupportedVoidFunctionDelegationCheck();
    }