Dataexplorer viewlet (#3967)

* added initial data explorer viewlet

* added dataexplorer contribution point

* removed test view

* remove unused imports

* added flag and tests

* CR comments

* added icon for data explorer

src/sqltest/parts/dataExplorer/dataExplorerViewlet.test.ts

@@ -0,0 +1,57 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import * as assert from 'assert';
+import * as Platform from 'vs/platform/registry/common/platform';
+import { ViewletDescriptor, Extensions, Viewlet, ViewletRegistry } from 'vs/workbench/browser/viewlet';
+import * as Types from 'vs/base/common/types';
+
+suite('Data Explorer Viewlet', () => {
+
+	class DataExplorerTestViewlet extends Viewlet {
+
+		constructor() {
+			super('dataExplorer', null, null, null);
+		}
+
+		public layout(dimension: any): void {
+			throw new Error('Method not implemented.');
+		}
+	}
+
+	test('ViewletDescriptor API', function () {
+		let d = new ViewletDescriptor(DataExplorerTestViewlet, 'id', 'name', 'class', 1);
+		assert.strictEqual(d.id, 'id');
+		assert.strictEqual(d.name, 'name');
+		assert.strictEqual(d.cssClass, 'class');
+		assert.strictEqual(d.order, 1);
+	});
+
+	test('Editor Aware ViewletDescriptor API', function () {
+		let d = new ViewletDescriptor(DataExplorerTestViewlet, 'id', 'name', 'class', 5);
+		assert.strictEqual(d.id, 'id');
+		assert.strictEqual(d.name, 'name');
+
+		d = new ViewletDescriptor(DataExplorerTestViewlet, 'id', 'name', 'class', 5);
+		assert.strictEqual(d.id, 'id');
+		assert.strictEqual(d.name, 'name');
+	});
+
+	test('Data Explorer Viewlet extension point and registration', function () {
+		assert(Types.isFunction(Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).registerViewlet));
+		assert(Types.isFunction(Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).getViewlet));
+		assert(Types.isFunction(Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).getViewlets));
+
+		let oldCount = Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).getViewlets().length;
+		let d = new ViewletDescriptor(DataExplorerTestViewlet, 'dataExplorer-test-id', 'name');
+		Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).registerViewlet(d);
+		let retrieved =  Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).getViewlet('dataExplorer-test-id');
+		assert(d === retrieved);
+		let newCount = Platform.Registry.as<ViewletRegistry>(Extensions.Viewlets).getViewlets().length;
+		assert.equal(oldCount + 1, newCount);
+	});
+});