code: function(method, path, data) {
          const pendingReq = new ExpectedRequest(method, path, data);
          this.expectedRequests.push(pendingReq);
          return pendingReq;
      }
docs: Create an expected request.
  @param {string} method The HTTP method
  @param {string} path The path (which can be partial)
  @param {Object} data The expected data.
  @return {Request} An expected request.