### Question:
AdManagerInternals { public static Internals getInstance() { return INSTANCE; }  static Internals getInstance();  }### Answer:
@Test public void testGetInstance() { Internals internals = AdManagerInternals.getInstance(); String userAgent = internals.getUserAgentCombiner().getUserAgent("test"); assertTrue(userAgent.contains("DfpApi")); assertFalse(userAgent.contains("DfaApi")); assertFalse(userAgent.contains("AwApi")); }