bdd$1 = function bddInterface(suite) {
	  var suites = [suite];
	  suite.on(EVENT_FILE_PRE_REQUIRE$2, function (context, file, mocha) {
	    var common$1 = common(suites, context, mocha);
	    context.before = common$1.before;
	    context.after = common$1.after;
	    context.beforeEach = common$1.beforeEach;
	    context.afterEach = common$1.afterEach;
	    context.run = mocha.options.delay && common$1.runWithSuite(suite);
	    /**
	     * Describe a "suite" with the given `title`
	     * and callback `fn` containing nested suites
	     * and/or tests.
	     */

	    context.describe = context.context = function (title, fn) {
	      return common$1.suite.create({
	        title: title,
	        file: file,
	        fn: fn
	      });
	    };
	    /**
	     * Pending describe.
	     */


	    context.xdescribe = context.xcontext = context.describe.skip = function (title, fn) {
	      return common$1.suite.skip({
	        title: title,
	        file: file,
	        fn: fn
	      });
	    };
	    /**
	     * Exclusive suite.
	     */


	    context.describe.only = function (title, fn) {
	      return common$1.suite.only({
	        title: title,
	        file: file,
	        fn: fn
	      });
	    };
	    /**
	     * Describe a specification or test-case
	     * with the given `title` and callback `fn`
	     * acting as a thunk.
	     */


	    context.it = context.specify = function (title, fn) {
	      var suite = suites[0];

	      if (suite.isPending()) {
	        fn = null;
	      }

	      var test$1 = new test(title, fn);
	      test$1.file = file;
	      suite.addTest(test$1);
	      return test$1;
	    };
	    /**
	     * Exclusive test-case.
	     */


	    context.it.only = function (title, fn) {
	      return common$1.test.only(mocha, context.it(title, fn));
	    };
	    /**
	     * Pending test case.
	     */


	    context.xit = context.xspecify = context.it.skip = function (title) {
	      return context.it(title);
	    };
	  });
	}
BDD-style interface:

     describe('Array', function() {
       describe('#indexOf()', function() {
         it('should return -1 when not present', function() {
           // ...
         });

         it('should return the index when present', function() {
           // ...
         });
       });
     });

@param {Suite} suite Root suite.