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

• ITDD - Instrumentation TDD for Android

##Table of Contents

• About
• Setup
• Request verification
• Logging
• Unit Tests with Robolectric
• Android Sample Project
• License

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:0.1.3'
}

####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();

##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();

##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.