tests: Set up initial examples workspace when launching

- microsoft/vscode#69335
- microsoft/vscode#78740
- https://stackoverflow.com/questions/55456193/testing-a-vscode-extension-that-involves-opening-a-folder-workspace

Fixes #26, follow-up for #5/#12

src/test/runTest.ts

@@ -1,4 +1,5 @@
 import * as path from 'path';
+import * as fs_promises from 'fs/promises';
 
 import { runTests } from '@vscode/test-electron';
 
@@ -12,11 +13,16 @@ async function main() {
 		// Passed to --extensionTestsPath
 		const extensionTestsPath = path.resolve(__dirname, './suite/index');
 
+		const exampleRoot = path.resolve(extensionDevelopmentPath, './src/test/examples');
+		const exampleBasenames = await fs_promises.readdir(exampleRoot);
+		const examplePaths = exampleBasenames.map((dir) => path.resolve(exampleRoot, dir));
+
 		// Download VS Code, unzip it and run the integration test
 		await runTests({
 			extensionDevelopmentPath,
 			extensionTestsPath,
-			launchArgs: ['--disable-extensions']
+			// open a multi-folder workspace with all test example dirs
+			launchArgs: ['--disable-extensions'].concat(examplePaths)
 		});
 	} catch (err) {
 		console.error('Failed to run tests');

src/test/suite/toxTaskProvider.test.ts

@@ -1,4 +1,5 @@
 import { doesNotMatch, strict as assert } from 'assert';
+import * as path from 'path';
 
 // You can import and use all API from the 'vscode' module
 // as well as import your extension to test it
@@ -13,17 +14,16 @@ suite('ToxTaskProvider Test Suite', () => {
 	test('getting tox tasks', async() => {
 		const dir = utils.getExampleDir("allenvs");
 
-		const allEnvsWorkspaceFolder = {
-			uri: vscode.Uri.file(dir),
-			name: "AllEnvs",
-			index: 0,
-		};
-
-		vscode.workspace.updateWorkspaceFolders(0, null, allEnvsWorkspaceFolder);
+		// make sure we started with the expected workspace, as we can't change
+		// workspaces in tests:
+		// https://github.com/microsoft/vscode/issues/69335
+		assert.ok(vscode.workspace.workspaceFolders);
+		assert.equal(path.basename(vscode.workspace.workspaceFolders[0].uri.fsPath), "allenvs");
 
 		const toxTaskProvider = new tasks.ToxTaskProvider(dir);
 		const toxTasks = await toxTaskProvider.provideTasks();
-		assert.equal(toxTasks?.length, 3);
+		assert.equal(toxTasks?.length, 6);
+		// from allenvs workspace folder
 		assert.equal(toxTasks[0].name, "one");
 		assert.equal(toxTasks[1].name, "two");
 		assert.equal(toxTasks[2].name, "three");