MockInstallation.md

Testing/Mocks: Installing/Uninstalling the Transport Mocks

All of the transport classes in this library are designed to be mockable. There is a MockTransports API that enables mocking of HTTP requests and WebSockets without any changes to the source code.

import 'package:w_transport/mock.dart' show MockTransports;

Installation

These transport mocks can then be installed at any time.

MockTransports.install();

Once installed, any transport class that is constructed will be wrapped in a mock-aware class. This is completely transparent and has no immediate effect.

When the transport mocks are installed, it is up to you to define how requests and WebSockets are handled. In other words, you play the role of the server so that a real one isn't necessary.

To do this, you can set up expectations and/or handlers. Expectations are one-time only, while handlers continue to serve requests/WebSockets until canceled.

Check out the HTTP and WebSocket guides for expectations and handlers:

• Expecting requests (one-time use)
• Request handlers (many-time use)
• Expecting WebSocket connections (one-time use)
• WebSocket connections handlers (many-time use)

Uninstallation

The transport mocks should always be uninstalled in order to ensure that you return to a clean state. Additionally, we recommend utilizing MockTransports.verifyNoOutstandingExceptions to ensure that there are no unresolved requests or unsatisfied expectations.

A good pattern to follow in tests looks like this:

import 'package:test/test.dart';
import 'package:w_transport/mock.dart';

void main() {
  setUp(() {
    MockTransports.install();
  });
  
  tearDown(() async {
    MockTransports.verifyNoOutstandingExceptions();
    await MockTransports.uninstall();
  });
}

Note that the call to uninstall() is async because it may have to cancel in-flight requests or tear down open websocket connections.