### Question:
SystemPropertyConfigSource extends PayaraConfigSource implements ConfigSource { @Override public String getValue(String propertyName) { String result; result = System.getProperty(propertyName); if (result == null && context != null) { result = context.getConfigBean().getSystemPropertyValue(propertyName); if (result == null) { result = domainConfiguration.getSystemPropertyValue(propertyName); } } return result; } SystemPropertyConfigSource();   SystemPropertyConfigSource(boolean test); @Override Map<String, String> getProperties(); @Override int getOrdinal(); @Override String getValue(String propertyName); @Override String getName();  }### Answer:
@Test public void testAddProperty() { assertNull(source.getValue("NoProperty")); System.setProperty("NoProperty", "test"); assertEquals("test", source.getValue("NoProperty")); }