mock_web_server 4.1.0

MockWebServer #

build status

A flexible Dart web server that can be used to script tests and web server interactions

Summary #

The best way to do integration tests, or to reproduce specific edge cases, is to be able to script the interaction between the software that is being tested and the web server.

MockWebServer aims to facility testing by offering a flexible stand alone Server that will respond with a given script (or forward the request to your dispatcher).

MockWebServer is based on the library of the same name created by Square for Java.

Usage #

Starting it #

MockWebServer can run in a given port or an ephemeral one

new MockWebServer(); // Will use an ephemeral port picked by the system
new MockWebServer(port: 8081); // Will use 8081

To start it just do

MockWebServer server = new MockWebServer();
server.start();

Once you have the server running you will want to get the url of it, so that you can configure your app to connect there

server.url; // will return http://127.0.0.1:8081
server.port; // 8081
server.host; // 127.0.0.1

Adding responses to the queue #

Once the server is started, you can queue the responses that you want. The response queue is First In First Out

// Enqueue an empty body with response code 401
server.enqueue(httpCode: 401);

// Response code defaults to 200, so this will be a 200 with the given json as the body
server.enqueue(body: '{ "message" : "hi"}');

// HTTP 200 with empty body and some header
Map<String, String> headers = new Map();
headers["X-Server"] = "MockDart";
server.enqueue(headers: headers);

// All the parameters are optional so you can mix and match according to what you need
server.enqueue(httpCode: 201, body: "answer", headers: headers, duration: duration);

// You can always call enqueueResponse() to directly enqueue a MockResponse
Map<String, String> headers = new Map();
headers["X-Server"] = "MockDart";

var mockResponse = new MockResponse()
  ..httpCode = 201
  ..body = "Created"
  ..headers = headers
  ..delay = new Duration(seconds: 2);

server.enqueueResponse(mockResponse);

Delaying the response #

To test timeouts or race conditions you may want to have the server take some time

server.enqueue(delay: new Duration(seconds: 2), httpCode: 201);
Stopwatch stopwatch = new Stopwatch();
stopwatch.start();

HttpClientResponse response = request(path: "");

stopwatch.stop();
expect(stopwatch.elapsed.inMilliseconds, greaterThanOrEqualTo(2000));
expect(response.statusCode, 201);

Validating that the request was correct #

You may want to check that your app is sending the correct requests. To do so you can obtain the requests that have been made to the server. The request queue is Last In First Out

server.enqueue(body: "a");
server.enqueue(body: "b");
server.enqueue(body: "c");

request(path: "first");
request(path: "second");
request(path: "third");

// takeRequest is FIFO
// You should probably assign takeRequest() to a var so that you can 
// validate multiple things.
expect(server.takeRequest().headers['x-header'], "nosniff");
expect(server.takeRequest().method, "GET");
expect(server.takeRequest().uri.path, "/third");

Using a dispatcher for fine-grained routing #

If you want more control than what the FIFO queue offers, you can set a dispatcher and set the logic there.

var dispatcher = (HttpRequest request) {
  if (request.uri.path == "/users") {
    return new MockResponse()
      ..httpCode = 200
      ..body = "working";
  } else if (request.uri.path == "/users/1") {
    return new MockResponse()..httpCode = 201;
  }

  return new MockResponse()..httpCode = 404;
};

server.dispatcher = dispatcher;

HttpClientResponse response = request(path: "unknown");
expect(response.statusCode, 404);

response = request(path: "users");
expect(response.statusCode, 200);
expect(read(response), "working");

response = request(path: "users/1");
expect(response.statusCode, 201);

TLS #

You can start the server using TLS by passing the certificate parameter when creating the instance of MockWebServer. For example using the included certificates and the resource library you would do

var chainRes =
    new Resource('package:mock_web_server/certificates/server_chain.pem');
List<int> chain = await chainRes.readAsBytes();

var keyRes =
    new Resource('package:mock_web_server/certificates/server_key.pem');
List<int> key = await keyRes.readAsBytes();

Certificate certificate = new Certificate()
  ..password = "dartdart"
  ..key = key
  ..chain = chain;

MockWebServer _server =
    new MockWebServer(certificate: certificate);

If you do so, and your client validates the certs, you will need to use a proper SecurityContext, for example using the included trusted_certs.pem

var certRes =
    new Resource('package:mock_web_server/certificates/trusted_certs.pem');
List<int> cert = await certRes.readAsBytes();

SecurityContext clientContext = new SecurityContext()
   ..setTrustedCertificatesBytes(cert);
    
var client = new HttpClient(context: clientContext);

Please check the tests of MockWebServer to see a complete example of this.

IPv6 #

If want to use IPv6, you can pass addressType: InternetAddressType.IP_V6 in the constructor to have the server use it. Keep in mind that the host property will then be ::1 instead of 127.0.0.1.

MockWebServer _server =
        new MockWebServer(port: 8030, addressType: InternetAddressType.IP_V6);

Setting a default response #

In some scenarions, if there's nothing on queue and there's no dispatcher, you may want the server to default to a response (e.g 404) instead of throwing an exception.

_server.defaultResponse = MockResponse()..httpCode = 404;

Stopping #

During the tearDown of your tests you should stop the server. server.shutdown() will do.

Changelog #

4.1.0 - Aug 04, 2019 #

  • Added defaultResponse

4.0.0 - Dec 06, 2018 #

  • Changed takeRequest() to be FIFO like Square's implementation

Breaking #

  • All your tests need to be updated to use takeRequest() according to above

3.0.0 - Nov 27, 2018 #

Changed #

  • Updated code to support Dart 2
  • Added SDK constraint to Dart 2

Breaking #

  • Dart 2 is required

2.1.0 - Oct 21, 2017 #

Changed #

  • Using a MockWebServer class to return the stored requests
  • Loading the body of stored requests to facilitate validation
  • Using a queue

2.0.1 - Oct 15, 2017 #

Changed #

  • Better request count management to avoid external modifications

2.0.0 - Oct 15, 2017 #

Breaking #

  • Support for TLS now receives the cert config for better flexibility and also to remove resource from the dependencies

1.3.0 - Oct 11, 2017 #

Added #

  • Support for TLS
  • Support to set the Inet Address type to IPv6, default value is IPv4

Changed #

  • Better property handling

1.2.0 - Aug 25, 2017 #

Added #

  • Support for async dispatcher

1.1.0 - Aug 20, 2017 #

Added #

  • Request count
  • Comprehensive documentation

Fixed #

  • Bug when delaying would be ignored if a Dispatcher was set

1.0.0 - Aug 17, 2017 #

Added #

  • All the basic functionality

example/example.dart

/*
 * Copyright (C) 2017 Miguel Castiblanco
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import 'package:mock_web_server/mock_web_server.dart';
import 'package:test/test.dart';
import 'dart:io';
import 'dart:async';
import 'dart:convert';
import 'package:resource/resource.dart' show Resource;

MockWebServer _server;

void main() {
  setUp(() {
    _server = new MockWebServer();
    _server.start();
  });

  tearDown(() {
    _server.shutdown();
  });

  test("Set response code", () async {
    _server.enqueue(httpCode: 401);
    HttpClientResponse response = await _get("");
    expect(response.statusCode, 401);
  });

  test("Set body", () async {
    _server.enqueue(body: "something");
    HttpClientResponse response = await _get("");
    expect(await _read(response), "something");
  });

  test("Set headers", () async {
    Map<String, String> headers = new Map();
    headers["X-Server"] = "MockDart";

    _server.enqueue(body: "Created", httpCode: 201, headers: headers);
    HttpClientResponse response = await _get("");
    expect(response.statusCode, 201);
    expect(response.headers.value("X-Server"), "MockDart");
    expect(await _read(response), "Created");
  });

  test("Set body and response code", () async {
    _server.enqueue(body: "Created", httpCode: 201);
    HttpClientResponse response = await _get("");
    expect(response.statusCode, 201);
    expect(await _read(response), "Created");
  });

  test("Set body, response code, and headers", () async {
    Map<String, String> headers = new Map();
    headers["X-Server"] = "MockDart";

    _server.enqueue(body: "Created", httpCode: 201, headers: headers);
    HttpClientResponse response = await _get("");
    expect(response.statusCode, 201);
    expect(response.headers.value("X-Server"), "MockDart");
    expect(await _read(response), "Created");
  });

  test("Queue", () async {
    _server.enqueue(body: "hello");
    _server.enqueue(body: "world");
    HttpClientResponse response = await _get("");
    expect(await _read(response), "hello");

    response = await _get("");
    expect(await _read(response), "world");
  });

  test("Take requests & request count", () async {
    _server.enqueue(body: "a");
    _server.enqueue(body: "b");
    _server.enqueue(body: "c");
    await _get("first");
    await _get("second");
    await _get("third");

    expect(_server.takeRequest().uri.path, "/first");
    expect(_server.takeRequest().uri.path, "/second");
    expect(_server.takeRequest().uri.path, "/third");
    expect(_server.requestCount, 3);
  });

  test("Request count", () async {
    _server.enqueue(httpCode: HttpStatus.unauthorized);

    await _get("first");

    expect(_server.takeRequest().uri.path, "/first");
    expect(_server.requestCount, 1);
  });

  test("Dispatcher", () async {
    var dispatcher = (HttpRequest request) async {
      if (request.uri.path == "/users") {
        return new MockResponse()
          ..httpCode = 200
          ..body = "working";
      } else if (request.uri.path == "/users/1") {
        return new MockResponse()..httpCode = 201;
      } else if (request.uri.path == "/delay") {
        return new MockResponse()
          ..httpCode = 200
          ..delay = new Duration(milliseconds: 1500);
      }

      return new MockResponse()..httpCode = 404;
    };

    _server.dispatcher = dispatcher;

    HttpClientResponse response = await _get("unknown");
    expect(response.statusCode, 404);

    response = await _get("users");
    expect(response.statusCode, 200);
    expect(await _read(response), "working");

    response = await _get("users/1");
    expect(response.statusCode, 201);

    Stopwatch stopwatch = new Stopwatch()..start();
    response = await _get("delay");
    stopwatch.stop();
    expect(stopwatch.elapsed.inMilliseconds,
        greaterThanOrEqualTo(new Duration(milliseconds: 1500).inMilliseconds));
    expect(response.statusCode, 200);
  });

  test("Enqueue MockResponse", () async {
    Map<String, String> headers = new Map();
    headers["X-Server"] = "MockDart";

    var mockResponse = new MockResponse()
      ..httpCode = 201
      ..body = "Created"
      ..headers = headers;

    _server.enqueueResponse(mockResponse);
    HttpClientResponse response = await _get("");
    expect(response.statusCode, 201);
    expect(response.headers.value("X-Server"), "MockDart");
    expect(await _read(response), "Created");
  });

  test("Delay", () async {
    _server.enqueue(delay: new Duration(seconds: 2), httpCode: 201);
    Stopwatch stopwatch = new Stopwatch()..start();
    HttpClientResponse response = await _get("");

    stopwatch.stop();
    expect(stopwatch.elapsed.inMilliseconds,
        greaterThanOrEqualTo(new Duration(seconds: 2).inMilliseconds));
    expect(response.statusCode, 201);
  });

  test('Parallel delay', () async {
    String body70 = "70 milliseconds";
    String body40 = "40 milliseconds";
    String body20 = "20 milliseconds";
    _server.enqueue(delay: new Duration(milliseconds: 40), body: body40);
    _server.enqueue(delay: new Duration(milliseconds: 70), body: body70);
    _server.enqueue(delay: new Duration(milliseconds: 20), body: body20);

    Completer completer = new Completer();
    List<String> responses = new List();

    _get("").then((res) async {
      // 40 milliseconds
      String result = await _read(res);
      responses.add(result);
    });

    _get("").then((res) async {
      // 70 milliseconds
      String result = await _read(res);
      responses.add(result);

      // complete on the longer operation
      completer.complete();
    });

    _get("").then((res) async {
      // 20 milliseconds
      String result = await _read(res);
      responses.add(result);
    });

    await completer.future;

    // validate that the responses happened in order 20, 40, 70
    expect(responses[0], body20);
    expect(responses[1], body40);
    expect(responses[2], body70);
  });

  test("Request specific port IPv4", () async {
    MockWebServer _server = new MockWebServer(port: 8029);
    await _server.start();

    RegExp url = new RegExp(r'(?:http[s]?:\/\/(?:127\.0\.0\.1):8029\/)');
    RegExp host = new RegExp(r'(?:127\.0\.0\.1)');

    expect(url.hasMatch(_server.url), true);
    expect(host.hasMatch(_server.host), true);
    expect(_server.port, 8029);

    _server.shutdown();
  });

  test("Request specific port IPv6", () async {
    MockWebServer _server =
        new MockWebServer(port: 8030, addressType: InternetAddressType.IPv6);
    await _server.start();

    RegExp url = new RegExp(r'(?:http[s]?:\/\/(?:::1):8030\/)');
    RegExp host = new RegExp(r'(?:::1)');

    expect(url.hasMatch(_server.url), true);
    expect(host.hasMatch(_server.host), true);
    expect(_server.port, 8030);

    _server.shutdown();
  });

  test("TLS info", () async {
    var chainRes =
        new Resource('package:mock_web_server/certificates/server_chain.pem');
    List<int> chain = await chainRes.readAsBytes();

    var keyRes =
        new Resource('package:mock_web_server/certificates/server_key.pem');
    List<int> key = await keyRes.readAsBytes();

    Certificate certificate = new Certificate()
      ..password = "dartdart"
      ..key = key
      ..chain = chain;

    MockWebServer _server =
        new MockWebServer(port: 8029, certificate: certificate);
    await _server.start();

    RegExp url = new RegExp(r'(?:https:\/\/(?:127\.0\.0\.1):8029\/)');
    RegExp host = new RegExp(r'(?:127\.0\.0\.1)');

    expect(url.hasMatch(_server.url), true);
    expect(host.hasMatch(_server.host), true);
    expect(_server.port, 8029);

    _server.shutdown();
  });

  test("TLS cert", () async {
    String body = "S03E08 You Are Not Safe";

    var chainRes =
        new Resource('package:mock_web_server/certificates/server_chain.pem');
    List<int> chain = await chainRes.readAsBytes();

    var keyRes =
        new Resource('package:mock_web_server/certificates/server_key.pem');
    List<int> key = await keyRes.readAsBytes();

    Certificate certificate = new Certificate()
      ..password = "dartdart"
      ..key = key
      ..chain = chain;

    MockWebServer _server =
        new MockWebServer(port: 8029, certificate: certificate);
    await _server.start();
    _server.enqueue(body: body);

    var certRes =
        new Resource('package:mock_web_server/certificates/trusted_certs.pem');
    List<int> cert = await certRes.readAsBytes();

    // Calling without the proper security context
    var clientErr = new HttpClient();

    expect(clientErr.getUrl(Uri.parse(_server.url)),
        throwsA(new TypeMatcher<HandshakeException>()));

    // Testing with security context
    SecurityContext clientContext = new SecurityContext()
      ..setTrustedCertificatesBytes(cert);

    var client = new HttpClient(context: clientContext);
    var request = await client.getUrl(Uri.parse(_server.url));
    String response = await _read(await request.close());

    expect(response, body);

    _server.shutdown();
  });

  test("Check take request", () async {
    _server.enqueue();

    HttpClient client = new HttpClient();
    HttpClientRequest request =
        await client.post(_server.host, _server.port, "test");
    request.headers.add("x-header", "nosniff");
    request.write("sample body");

    await request.close();
    StoredRequest storedRequest = _server.takeRequest();

    expect(storedRequest.method, "POST");
    expect(storedRequest.body, "sample body");
    expect(storedRequest.uri.path, "/test");
    expect(storedRequest.headers['x-header'], "nosniff");
  });

  test("default response", () async {
    _server.defaultResponse = MockResponse()..httpCode = 404;

    var response = await _get("");
    expect(response.statusCode, 404);
  });
}

_get(String path) async {
  HttpClient client = new HttpClient();
  HttpClientRequest request =
      await client.get(_server.host, _server.port, path);
  return await request.close();
}

Future<String> _read(HttpClientResponse response) async {
  StringBuffer body = new StringBuffer();
  Completer<String> completer = new Completer();

  response.transform(utf8.decoder).listen((data) {
    body.write(data);
  }, onDone: () {
    completer.complete(body.toString());
  });

  await completer.future;
  return body.toString();
}

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:


dependencies:
  mock_web_server: ^4.1.0

2. Install it

You can install packages from the command line:

with pub:


$ pub get

with Flutter:


$ flutter pub get

Alternatively, your editor might support pub get or flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:mock_web_server/mock_web_server.dart';
  
Popularity:
Describes how popular the package is relative to other packages. [more]
71
Health:
Code health derived from static analysis. [more]
98
Maintenance:
Reflects how tidy and up-to-date the package is. [more]
100
Overall:
Weighted score of the above. [more]
85
Learn more about scoring.

We analyzed this package on Aug 21, 2019, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.4.0
  • pana: 0.12.19

Platforms

Detected platforms: Flutter, other

Primary library: package:mock_web_server/mock_web_server.dart with components: io.

Health suggestions

Fix lib/mock_web_server.dart. (-2.48 points)

Analysis of lib/mock_web_server.dart reported 5 hints:

line 132 col 12: Use = to separate a named parameter from its default value.

line 134 col 18: Use = to separate a named parameter from its default value.

line 167 col 19: Use = to separate a named parameter from its default value.

line 168 col 19: Use = to separate a named parameter from its default value.

line 275 col 7: Future results in async function bodies must be awaited or marked unawaited using package:pedantic.

Dependencies

Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.0.0 <3.0.0
Dev dependencies
resource >=2.1.5 <3.0.0
test >=1.5.1 <2.0.0