assertTrue(customProperties.containsKey("Boolean"));
// Check the values went in
assertEquals("Wert \u00e4", customProperties.get("Schl\u00fcssel \u00e4"));
assertEquals(Boolean.TRUE, customProperties.get("Boolean"));
assertTrue(customProperties.containsValue(Boolean.TRUE));
assertTrue(customProperties.containsValue("Wert \u00e4"));
// Check that things that aren't in aren't in
assertFalse(customProperties.containsKey("False Boolean"));
assertFalse(customProperties.containsValue(Boolean.FALSE));