### Question:
ConfigSourceMap extends AbstractMap<String, String> implements Map<String, String>, Serializable { public void forEach(final BiConsumer<? super String, ? super String> action) { for (String name : keySet()) { action.accept(name, delegate.getValue(name)); } } ConfigSourceMap(final ConfigSource delegate); int size(); boolean isEmpty(); boolean containsKey(final Object key); String get(final Object key); Set<String> keySet(); Collection<String> values(); Set<Entry<String, String>> entrySet(); void forEach(final BiConsumer<? super String, ? super String> action);  }### Answer:
@Test public void testForEach() { final Set<String> need = new HashSet<>(MANY_MAP.keySet()); final ConfigSourceMap csm = new ConfigSourceMap(MANY_CONF_SRC); csm.forEach((k, v) -> { assertEquals(MANY_MAP.get(k), v); assertTrue(need.remove(k)); }); assertTrue(need.isEmpty(), "keys left in set"); }