CredentialFromAccessTokenProviderClassFactory { public static Credential credential( AccessTokenProvider accessTokenProvider, Collection<String> scopes) throws IOException, GeneralSecurityException { return getCredentialFromAccessTokenProvider(accessTokenProvider, scopes); }  static Credential credential(
      AccessTokenProvider accessTokenProvider, Collection<String> scopes); static Credential credential(
      Configuration config, List<String> keyPrefixes, Collection<String> scopes);  }
@Test public void testCreateCredentialFromProviderClassFactory() throws IOException, GeneralSecurityException { Credential credential = CredentialFromAccessTokenProviderClassFactory.credential( config, ImmutableList.of(TEST_PROPERTY_PREFIX), ImmutableList.of()); assertThat(credential.getAccessToken()).isEqualTo(TestingAccessTokenProvider.FAKE_ACCESS_TOKEN); assertThat(credential.getExpirationTimeMilliseconds()) .isEqualTo(TestingAccessTokenProvider.EXPIRATION_TIME_MILLISECONDS); }