add test cases for markOnly method

test/unit/test.spec.js

@@ -2,6 +2,7 @@
 
 var mocha = require('../../lib/mocha');
 var Test = mocha.Test;
+var sinon = require('sinon');
 
 describe('Test', function() {
   describe('.clone()', function() {
@@ -83,4 +84,40 @@ describe('Test', function() {
       expect(this._test.isPending(), 'to be', true);
     });
   });
+
+  describe('.markOnly()', function() {
+    var sandbox;
+
+    beforeEach(function() {
+      sandbox = sinon.createSandbox();
+    });
+
+    afterEach(function() {
+      sandbox.restore();
+    });
+
+    it('should call appendOnlyTest on parent', function() {
+      var test = new Test('foo');
+      var spy = sandbox.spy();
+      test.parent = {
+        appendOnlyTest: spy
+      };
+
+      test.markOnly();
+
+      expect(spy, 'was called times', 1);
+    });
+
+    it('should pass itself as an argument', function() {
+      var test = new Test('foo');
+      var spy = sandbox.spy();
+      test.parent = {
+        appendOnlyTest: spy
+      };
+
+      test.markOnly();
+
+      expect(spy.getCall(0).args[0], 'to be', test);
+    });
+  });
 });