@Test
public void testGetKeys() {

    Configuration config = Configuration.current();
    DefaultConfigurationSnapshot snapshot = new DefaultConfigurationSnapshot(config,
            Arrays.asList("confkey1", "confkey2", "confkey3"));
    assertThat(snapshot.getKeys()).contains("confkey1");
    assertThat(snapshot.getKeys()).contains("confkey2");
    assertThat(snapshot.getKeys()).contains("confkey3");
    assertThat(snapshot.getKeys()).doesNotContain("confkey4");
    assertThat(snapshot.getKeys()).doesNotContain("foo");
}