### Question:
SecretsDirConfigSource extends PayaraConfigSource implements ConfigSource { @Override public Set<String> getPropertyNames() { return properties.keySet(); } SecretsDirConfigSource();   SecretsDirConfigSource(Path directory); @Override Map<String, String> getProperties(); @Override Set<String> getPropertyNames(); @Override int getOrdinal(); @Override String getValue(String property); @Override String getName();  }### Answer:
@Test public void testGetPropertyNames() { assertEquals(new HashSet<>(asList("property1", "property2")), source.getPropertyNames()); }