     // when
     Auth.auth()
       .signIn(with: facebookCredential)
-      .flatMap { [weak authBackend] (authResult) -> Future<AuthDataResult, Error> in
+      .flatMap { (authResult) -> Future<AuthDataResult, Error> in
         XCTAssertEqual(authResult.additionalUserInfo?.profile,
                        UserTests.googleProfile as [String: NSString])
         XCTAssertEqual(authResult.additionalUserInfo?.username,

                       FacebookAuthProviderID)
        XCTAssertEqual(Auth.auth().currentUser, authResult.user)

        authBackend?.providerCredentials = facebookCredentials
        authBackend?
          .verifyAssertionCallback = .failure(FIRAuthErrorUtils
            .accountExistsWithDifferentCredentialError(
              withEmail: UserTests.userName,

    var email: String
    var localID: String
    var phoneNumber: String? = nil
    var userInfo: [String: String]? = [:]
  }

  fileprivate static let phoneNumber = "12345658"
