Simple web server component (#9648)

* Simple web server component

* More testing

extensions/azurecore/src/test/account-provider/utils/simpleWebServer.test.ts

@@ -0,0 +1,65 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as should from 'should';
+import 'mocha';
+import axios from 'axios';
+
+import { SimpleWebServer } from '../../../account-provider/utils/simpleWebServer';
+
+let server: SimpleWebServer;
+
+// These tests don't work on Linux systems because gnome-keyring doesn't like running on headless machines.
+describe('AccountProvider.SimpleWebServer', function (): void {
+	beforeEach(async function (): Promise<void> {
+		server = new SimpleWebServer();
+	});
+
+	it('Starts up and returns a port', async function (): Promise<void> {
+		const port = await server.startup();
+		should(port).be.any.String().and.not.be.undefined().and.not.be.null();
+	});
+
+	it('Double startup should fail', async function (): Promise<void> {
+		await server.startup();
+		server.startup().should.be.rejected();
+	});
+
+	it('404 on unknown requests', async function (): Promise<void> {
+		const status = 404;
+
+		const server = new SimpleWebServer();
+		const port = await server.startup();
+		try {
+			const result = await axios.get(`http://localhost:${port}/hello`);
+			should(result).be.undefined();
+		} catch (ex) {
+			should(ex.response.status).equal(status);
+		}
+	});
+
+	it('Responds to GET requests', async function (): Promise<void> {
+		const msg = 'Hello World';
+		const status = 200;
+
+		const server = new SimpleWebServer();
+		const port = await server.startup();
+		server.on('/hello', (req, reqUrl, res) => {
+			res.writeHead(status);
+			res.write(msg);
+			res.end();
+		});
+
+		const response = await axios.get(`http://localhost:${port}/hello`);
+		should(response.status).equal(status);
+		should(response.data).equal(msg);
+	});
+
+	it('Server shuts off', async function (): Promise<void> {
+		await server.startup();
+		server.shutdown().should.not.be.rejected();
+	});
+
+});