code: function expectAliClaimKeys() {
      return bobTestClient.awaitOneTimeKeyUpload().then((keys) => {
          aliTestClient.httpBackend.when(
              "POST", "/keys/claim",
          ).respond(200, function(path, content) {
              const claimType = content.one_time_keys[bobUserId][bobDeviceId];
              expect(claimType).toEqual("signed_curve25519");
              let keyId = null;
              for (keyId in keys) {
                  if (bobTestClient.oneTimeKeys.hasOwnProperty(keyId)) {
                      if (keyId.indexOf(claimType + ":") === 0) {
                          break;
                      }
                  }
              }
              const result = {};
              result[bobUserId] = {};
              result[bobUserId][bobDeviceId] = {};
              result[bobUserId][bobDeviceId][keyId] = keys[keyId];
              return {one_time_keys: result};
          });
      }).then(() => {
          // it can take a while to process the key query, so give it some extra
          // time, and make sure the claim actually happens rather than ploughing on
          // confusingly.
          return aliTestClient.httpBackend.flush("/keys/claim", 1, 500).then((r) => {
              expect(r).toEqual(1, "Ali did not claim Bob's keys");
          });
      });
  }
docs: Set an expectation that ali will claim one of bob's keys; then flush the http request.
  
  @return {promise} resolves once the http request has completed.