common.js
function(mocha, test) {
        test.parent._onlyTests = test.parent._onlyTests.concat(test);
        mocha.options.hasOnly = true;
        return test;
      }
function(mocha, test) {
        test.parent._onlyTests = test.parent._onlyTests.concat(test);
        mocha.options.hasOnly = true;
        return test;
      }
function ( mocha , test ) { test . parent . _onlyTests = test . parent . _onlyTests . concat ( test ) ; mocha . options . hasOnly = true ; return test ; }
Exclusive test-case.

@param {Object} mocha
@param {Function} test
@returns {*}
Exclusive test - case .