public void test_combination() { CombinedReferenceData test = new CombinedReferenceData(BASE_DATA1, BASE_DATA2); assertEquals(test.containsValue(ID1), true); assertEquals(test.containsValue(ID2), true); assertEquals(test.containsValue(ID3), true); assertEquals(test.containsValue(ID4), false); assertEquals(test.getValue(ID1), VAL1); assertEquals(test.getValue(ID2), VAL2); assertEquals(test.getValue(ID3), VAL3); assertThrows(() -> test.getValue(ID4), ReferenceDataNotFoundException.class); assertEquals(test.findValue(ID1), Optional.of(VAL1)); assertEquals(test.findValue(ID2), Optional.of(VAL2)); assertEquals(test.findValue(ID3), Optional.of(VAL3)); assertEquals(test.findValue(ID4), Optional.empty()); }