public void uniqueScreenNames_AddExistingScreenName() { initilaizeFilteredTree(); Assert.IsNull(grantTrees.brailleTree); guiFuctions.addFilteredNodeToBrailleTree("screenName_1", "typeOfView_1", "viewName_1"); Assert.AreEqual(3, strategyMgr.getSpecifiedTree().Count(grantTrees.brailleTree)); // 3 => typeOfView-Node + Screen-Node + View-Node String idResult = guiFuctions.addFilteredNodeToBrailleTree("screenName_1", "typeOfView_2", "viewName_2"); // Same screenName Assert.IsNull(idResult); Assert.AreEqual(3, strategyMgr.getSpecifiedTree().Count(grantTrees.brailleTree)); // the node wasn't added }