@Override
    public void putAll(Map<? extends K, ? extends V> m) {
        // will throw UnsupportedOperationException; delegate anyway for testability
        underlying().putAll(m);
    }
@Test
    public void testDelegationOfUnsupportedFunctionPutAll() {
        new PCollectionsHashMapWrapperDelegationChecker<>()
            .defineMockConfigurationForVoidMethodInvocation(mock -> mock.putAll(eq(Collections.emptyMap())))
            .defineWrapperVoidMethodInvocation(wrapper -> wrapper.putAll(Collections.emptyMap()))
            .doUnsupportedVoidFunctionDelegationCheck();
    }