ConfigValue implements Serializable { ImmutableSet<String> getPrefixes() { return prefixedValues.keySet().stream() .flatMap(Collection::stream) .collect(ImmutableSet.toImmutableSet()); } ConfigValue(String currentValue, ImmutableMap<ImmutableSet<String>, String> prefixedValues);   }
@Test void testCase_getPrefixes() { assertThat(configValue.getPrefixes()).isEqualTo(ImmutableSet.of("Prefix1", "Prefix2", "Prefix3", "Prefix4")); }