RESTMock
REST API mocking made easy.
About
RESTMock is a library working on top of Square's okhttp/MockWebServer. It allows you to specify Hamcrest matchers to match HTTP requests and specify what response to return. It is as easy as:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnFile(200, "users/defunkt.json");
Article
Table of Contents
Setup
Here are the basic rules to set up RESTMock for Android
Step 1: Repository
Add it in your root build.gradle at the end of repositories:
allprojects {
repositories {
...
maven {
url "https://jitpack.io"
}
}
}
Step 2: Dependencies
Add the dependency
dependencies {
androidTestCompile 'com.github.andrzejchm.RESTMock:android:0.2.2'
}
Step 3: Start the server
It's good to start server before the tested application starts, there are few methods:
a) RESTMockTestRunner
To make it simple you can just use the predefined RESTMockTestRunner in your UI tests. It extends AndroidJUnitRunner:
defaultConfig {
...
testInstrumentationRunner 'io.appflate.restmock.android.RESTMockTestRunner'
}
b) RESTMockServerStarter
If you have your custom test runner and you can't extend RESTMockTestRunner, you can always just call the RESTMockServerStarter. Actually RESTMockTestRunner is doing exactly the same thing:
public class MyAppTestRunner extends AndroidJUnitRunner {
... @Override public void onCreate(Bundle arguments) {
super.onCreate(arguments);
RESTMockServerStarter.startSync(new AndroidAssetsFileParser(getContext()),new AndroidLogger());
...
}
...
}
Step 4: Specify Mocks
a) Files
By default, the RESTMockTestRunner uses AndroidAssetsFileParser as a mocks file parser, which reads the files from the assets folder. To make them visible for the RESTMock you have to put them in the correct folder in your project, for example:
.../src/androidTest/assets/users/defunkt.json This can be accessed like this:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnFile(200, "users/defunkt.json");
b) Strings
If the response You wish to return is simple, you can just specify a string:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnString(200, "{
}
");
c) MockResponse
If you wish to have a greater control over the response, you can pass the MockResponse
RESTMockServer.whenGET(pathContains("users/defunkt")).thenReturn(new MockResponse().setBody("").setResponseCode(401).addHeader("Header","Value"));
Step 5: Request Matchers
You can either use some of the predefined matchers from RequestMatchers util class, or create your own. remember to extend from RequestMatcher
Step 6: Specify API Endpoint
The most important step, in order for your app to communicate with the testServer, you have to specify it as an endpoint for all your API calls. For that, you can use the RESTMockServer.getUrl(). If you use Retrofit, it is as easy as:
RestAdapter adapter = new RestAdapter.Builder()
.baseUrl(RESTMockServer.getUrl())
...
.build();
take a look at #68 for better reference
Response chains
You can chain different responses for a single request matcher, all the thenReturn*() methods accept varags parameter with response, or you can call those methods multiple times on a single matcher, examples:
RESTMockServer.whenGET(pathEndsWith(path))
.thenReturnString("a single call")
.thenReturnEmpty(200)
.thenReturnFile("jsonFile.json");
or
RESTMockServer.whenGET(pathEndsWith(path))
.thenReturnString("a single call", "answer no 2", "answer no 3");
Response delays
Delaying responses is accomplished with the delay(TimeUnit timeUnit, long delay) method. Delays can be specified in chain, just like chaining responses:
RESTMockServer.whenGET(pathEndsWith(path))
.thenReturnString("a single call")
.delay(TimeUnit.SECONDS, 5)
.delay(TimeUnit.SECONDS, 10)
.delay(TimeUnit.SECONDS, 15);
or
RESTMockServer.whenGET(pathEndsWith(path))
.thenReturnString("a single call")
.delay(TimeUnit.SECONDS, 5, 10, 15);
Which will result in 1st response being delayed by 5 seconds, 2nd response by 10 seconds and 3rd, 4th, 5th... by 15 seconds.
Interleaving delays with responses
Check out this example:
RESTMockServer.whenGET(pathEndsWith(path))
.thenReturnString("1st call")
.delay(TimeUnit.SECONDS, 5)
.thenReturnString("2nd call")
.delay(TimeUnit.SECONDS, 10)
.delay(TimeUnit.SECONDS, 15)
.thenReturnString("3rd call")
.delay(TimeUnit.SECONDS, 20, 30, 40)this will result in 1st call being delayed by 5 seconds, 2nd call delayed by 10 seconds, 3rd call delayed by 15 seconds, another one by 20 seconds, and another by 30 seconds, and then every consecutive response with 40 seconds delay
Request verification
It is possible to verify which requests were called and how many times thanks to RequestsVerifier. All you have to do is call one of these:
//cheks if the GET request was invoked exactly 2 times RequestsVerifier.verifyGET(pathEndsWith("users")).exactly(2);
//cheks if the GET request was invoked at least 3 times RequestsVerifier.verifyGET(pathEndsWith("users")).atLeast(3);
//cheks if the GET request was invoked exactly 1 time RequestsVerifier.verifyGET(pathEndsWith("users")).invoked();
//cheks if the GET request was never invoked RequestsVerifier.verifyGET(pathEndsWith("users")).never();
Additionaly, you can manualy inspect requests received by RESTMockServer. All you have to do is to obtain them trough:
//gets 5 most recent requests received. (ordered from oldest to newest) RequestsVerifier.takeLast(5);
//gets 5 oldest requests received. (ordered from oldest to newest) RequestsVerifier.takeFirst(5);
//gets all GET requests. (ordered from oldest to newest) RequestsVerifier.takeAllMatching(isGET());
Logging
RESTMock supports logging events. You just have to provide the RESTMock with the implementation of RESTMockLogger. For Android there is an AndroidLogger implemented already. All you have to do is use the RESTMockTestRunner or call
RESTMockServerStarter.startSync(new AndroidAssetsFileParser(getContext()),new AndroidLogger());
or
RESTMockServer.enableLogging(RESTMockLogger) RESTMockServer.disableLogging()Unit Tests with Robolectric
If you want to write unit tests (no emulator or device necessary), you can use Robolectric to accomplish this. There is a sample project with Robolectric tests in androidsample.
One change you will need to make is to the file parser that you use. Since Robolectric doesn't create an actual device/emulator environment, you will need to use the local file system in lieu of getAssets(). A file parser for this has been provided for you, called, AndroidLocalFileParser. The AndroidLocalFileParser will look for files in the resources/ directory, which should be a child of /test/.
RESTMockServerStarter.startSync(new AndroidLocalFileParser(application),new AndroidLogger());
It is necessary to pass in the application variable at construction time, so that the Robolectric runner knows where to find the base path for files. You can retrieve the application at runtime using RuntimeEnvironment.application from within a Robolectric test.
Android Sample Project
You can check out the sample Android app with tests here
License
Copyright (C) 2016 Appflate.io 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.