public SplitBrainMergePolicy getMergePolicy(String className) {
        if (className == null) {
            throw new InvalidConfigurationException("Class name is mandatory!");
        }
        return getOrPutIfAbsent(mergePolicyMap, className, policyConstructorFunction);
    }
@Test
    public void getMergePolicy_withNotExistingMergePolicy() {
        assertThatThrownBy(() -> mergePolicyProvider.getMergePolicy("No such policy!"))
                .isInstanceOf(InvalidConfigurationException.class)
                .hasCauseInstanceOf(ClassNotFoundException.class);
    }