In memory http server for C# unit and integration tests

in-memory-http-server.cs

public static Task BasicHttpServer(string url, string outputHtml)
{
	return Task.Run(() =>
	{
		HttpListener listener = new HttpListener();
		listener.Prefixes.Add(url);
		listener.Start();

		// GetContext method blocks while waiting for a request. 
		HttpListenerContext context = listener.GetContext();
		HttpListenerResponse response = context.Response;

		Stream stream = response.OutputStream;
		var writer = new StreamWriter(stream);
		writer.Write(outputHtml);
		writer.Close();
	});
}

//
// Example
//

[Test]
public void should_return_html()
{
	// Arrange
	string url = GetLocalhostAddress();
	
	using(BasicHttpServer(url, "some html"))
	{
		var myhttpclient = new MyHttpClient(new Uri(url));

		// Act
		string actualContent = myhttpclient.Read();

		// Assert
		Assert.That(actualContent, Does.Contain("some html"));
	}
}

private string GetLocalhostAddress()
{
	var listener = new TcpListener(IPAddress.Loopback, 0);
	listener.Start();
	int port = ((IPEndPoint)listener.LocalEndpoint).Port;
	listener.Stop();

	return $"http://localhost:{port}/";
}