code: function (value1, value2, optMsg) {
                  var msg;
  
                  if (optMsg) {
                      msg = ariaUtilsString.substitute(optMsg, ['"' + value1 + '"', '"' + value2 + '"']);
                  } else {
                      msg = 'First value: "' + value1 + '" differs from the second: "' + value2 + '".';
                  }
  
                  this.assertTrue((value1 === value2), msg);
              }
docs: AssertEquals: Check that value1 is equal to value2
  @param {object} value1 the value to compare
  @param {object} value2 the value to compare
  @param {String} optMsg optional message to add to the failure description. It can contain placeholders %1
  and %2 which will be replaced accordingly with: %1 - value1, %2 - value2.