Increase variations in single select tree tests

Many problems with this unit test:
- Mouse clicks were not being tested, only API methods
- Folder selectable tree needs to test items also.
- Folder selectable tree needs to test items with folders previously selected, and folders with items previously selected
- Markup for folder selectable tree did not include a `tree-item` template and therefore created only folders and did not create any items (hence 4 folders/items are returned instead of the folders/correct 8 items).
- The selectItem method was being used to select folders.

test/markup/tree-markup.html

@@ -66,6 +66,13 @@
 				<ul class="tree-branch-children"></ul>
 				<div class="tree-loader" role="alert">Loading...</div>
 			</li>
+			<!-- item template -->
+			<li class="tree-item hidden" data-template="treeitem" role="treeitem">
+				<button class="tree-item-name">
+					<span class="glyphicon icon-item fueluxicon-bullet"></span>
+					<span class="tree-label">Example Item</span>
+				</button>
+			</li>
 		</ul>
 
 	</div>

test/tree-test.js

@@ -182,12 +182,13 @@ define(function (require) {
 
 		$selNode = $tree.find('.tree-branch:eq(1)');
 		$tree.tree('discloseFolder', $selNode.find('.tree-branch-header'));
-		equal($selNode.find('.tree-branch-children > li').length, 4, 'Folder has been populated with sub-folders');
+		equal($selNode.find('.tree-branch-children > li').length, 8, 'Folder has been populated with sub-folders and items');
 	});
 
 	test("Single item/folder selection works as designed", function () {
 		var $tree = $(html).find('#MyTree');
 
+		// multiSelect: false is the default
 		$tree.tree({
 			dataSource: this.dataSource
 		});
@@ -204,10 +205,24 @@ define(function (require) {
 			folderSelect: true
 		});
 
-		$tree.tree('selectItem', $tree.find('.tree-branch-name:eq(1)'));
-		equal($tree.tree('selectedItems').length, 1, 'Return single selected value');
-		$tree.tree('selectItem', $tree.find('.tree-branch-name:eq(2)'));
-		equal($tree.tree('selectedItems').length, 1, 'Return new single selected value');
+		$tree.tree('selectItem', $tree.find('.tree-item:eq(1)'));
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected item (none previously selected, 1st programatic selection)');
+
+		$tree.tree('selectFolder', $tree.find('.tree-branch-name:eq(1)'));
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected folder (item previously selected, 2nd programatic selection)');
+
+		$tree.tree('selectItem', $tree.find('.tree-item:eq(2)'));
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected item (folder previously selected, 3rd programatic selection)');
+
+		$tree.find('.tree-item:eq(1)').click();
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected item (item previously selected, 1st click selection)');
+
+		$tree.find('.tree-branch-name:eq(1)').click();
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected folder (item previously selected, 2nd click selection)');
+
+		$tree.find('.tree-item:eq(2)').click();
+		equal($tree.tree('selectedItems').length, 1, 'Return single selected item (folder previously selected, 3rd click selection)');
+
 	});
 
 	test("Multiple item/folder selection works as designed", function () {