code: function diffToMessage(diffedAssertionError) {
      var diff = diffedAssertionError.diff;
      var actual = "";
      var expected = "";
      for (var i = 0; i < diff.length; i++) {
          var diffType = diff[i][0];
          if (diffType === 1) {
              if (actual.length > 0) {
                  actual += ", ";
              }
              actual += "\"" + diff[i][1] + "\"";
          } else if (diffType === -1) {
              if (expected.length > 0) {
                  expected += ", ";
              }
              expected += "\"" + diff[i][1] + "\"";
          }
      }
      var message = "Differences: ";
      if (expected.length > 0) {
          message += "'expected': " + expected;
      }
      if (actual.length > 0) {
          if (expected.length > 0) {
              message += ", ";
          }
          message += "'actual': " + actual;
      }
      message += "\n";
      return  getMessages(diffedAssertionError).join(" ") + "\n" + message;
  
  }
docs: Given an AssertionError that has had diffs applied - and that means it has a diff property - provide the message
  for the AssertionError including details of the diffs.
  
  @method diffToMessage
  @private
  @param {AssertionError} diffedAssertionError an AssertionError that has a diff property containing diffs between the expected and
  actual values
  @return {String} the message that includes diff details