Add test view with a welcome button (microsoft#16215)

* Add test view with a welcome button

* Register registerTestController only when available.

package.json

@@ -2161,15 +2161,13 @@
                 }
             ]
         },
-        "views": {
-            "test": [
-                {
-                    "id": "python_tests",
-                    "name": "Python",
-                    "when": "testsDiscovered"
-                }
-            ]
-        },
+        "viewsWelcome": [
+            {
+                "view": "testing",
+                "contents": "Configure a test framework to see your tests here.\n[Configure Python Tests](command:python.configureTests)",
+                "when": "!testsDiscovered"
+            }
+        ],
         "yamlValidation": [
             {
                 "fileMatch": ".condarc",

src/client/testing/main.ts

@@ -8,6 +8,7 @@ import {
     Event,
     EventEmitter,
     OutputChannel,
+    test,
     TextDocument,
     Uri,
 } from 'vscode';
@@ -43,6 +44,7 @@ import {
 } from './common/types';
 import { TEST_OUTPUT_CHANNEL } from './constants';
 import { ITestingService } from './types';
+import { PythonTestController } from './testController/controller';
 
 @injectable()
 export class TestingService implements ITestingService {
@@ -116,6 +118,10 @@ export class UnitTestManagementService implements ITestManagementService, Dispos
         this.autoDiscoverTests(undefined).catch((ex) =>
             traceError('Failed to auto discover tests upon activation', ex),
         );
+
+        if (test && test.registerTestController) {
+            this.disposableRegistry.push(test.registerTestController(new PythonTestController()));
+        }
     }
     public async getTestManager(
         displayTestNotConfiguredMessage: boolean,

src/client/testing/serviceRegistry.ts

@@ -65,7 +65,6 @@ import { TestDisplay } from './display/picker';
 import { TestExplorerCommandHandler } from './explorer/commandHandlers';
 import { FailedTestHandler } from './explorer/failedTestHandler';
 import { TestTreeViewProvider } from './explorer/testTreeViewProvider';
-import { TreeViewService } from './explorer/treeView';
 import { TestingService, UnitTestManagementService } from './main';
 import { registerTypes as registerNavigationTypes } from './navigation/serviceRegistry';
 import { ITestExplorerCommandHandler } from './navigation/types';
@@ -148,7 +147,6 @@ export function registerTypes(serviceManager: IServiceManager) {
     serviceManager.addSingleton<ITestTreeViewProvider>(ITestTreeViewProvider, TestTreeViewProvider);
     serviceManager.addSingleton<ITestDataItemResource>(ITestDataItemResource, TestTreeViewProvider);
     serviceManager.addSingleton<ITestExplorerCommandHandler>(ITestExplorerCommandHandler, TestExplorerCommandHandler);
-    serviceManager.addSingleton<IExtensionSingleActivationService>(IExtensionSingleActivationService, TreeViewService);
     serviceManager.addSingleton<IExtensionSingleActivationService>(
         IExtensionSingleActivationService,
         FailedTestHandler,

src/client/testing/testController/controller.ts

@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+import { TestController } from 'vscode';
+/* eslint-disable */
+
+// This is a place holder for a controller
+export class PythonTestController implements TestController<any> {
+    public createWorkspaceTestRoot() {
+        return undefined;
+    }
+
+    public createDocumentTestRoot() {
+        return undefined;
+    }
+
+    public runTests() {}
+}