code: function expectAliQueryKeys() {
      // can't query keys before bob has uploaded them
      expect(bobTestClient.deviceKeys).toBeTruthy();
  
      const bobKeys = {};
      bobKeys[bobDeviceId] = bobTestClient.deviceKeys;
      aliTestClient.httpBackend.when("POST", "/keys/query")
              .respond(200, function(path, content) {
          expect(content.device_keys[bobUserId]).toEqual(
              {},
              "Expected Alice to key query for " + bobUserId + ", got " +
              Object.keys(content.device_keys),
          );
          const result = {};
          result[bobUserId] = bobKeys;
          return {device_keys: result};
      });
      return aliTestClient.httpBackend.flush("/keys/query", 1);
  }
docs: Set an expectation that ali will query bobs keys; then flush the http request.
  
  @return {promise} resolves once the http request has completed.