testing: rework discovery side of testing to new apis

src/vs/workbench/api/common/extHostTestingPrivateApi.ts

@@ -0,0 +1,44 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { Emitter } from 'vs/base/common/event';
+import { TestItemImpl } from 'vs/workbench/api/common/extHostTypes';
+import * as vscode from 'vscode';
+
+export const enum ExtHostTestItemEventType {
+	NewChild,
+	Disposed,
+	Invalidated,
+	SetProp,
+}
+
+export type ExtHostTestItemEvent =
+	| [evt: ExtHostTestItemEventType.NewChild, item: TestItemImpl]
+	| [evt: ExtHostTestItemEventType.Disposed]
+	| [evt: ExtHostTestItemEventType.Invalidated]
+	| [evt: ExtHostTestItemEventType.SetProp, key: keyof vscode.TestItem<never>, value: any];
+
+export interface IExtHostTestItemApi {
+	children: Map<string, TestItemImpl>;
+	parent?: TestItemImpl;
+	bus: Emitter<ExtHostTestItemEvent>;
+}
+
+const eventPrivateApis = new WeakMap<TestItemImpl, IExtHostTestItemApi>();
+
+/**
+ * Gets the private API for a test item implementation. This implementation
+ * is a managed object, but we keep a weakmap to avoid exposing any of the
+ * internals to extensions.
+ */
+export const getPrivateApiFor = (impl: TestItemImpl) => {
+	let api = eventPrivateApis.get(impl);
+	if (!api) {
+		api = { children: new Map(), bus: new Emitter() };
+		eventPrivateApis.set(impl, api);
+	}
+
+	return api;
+};