Test UI while idling resource is busy

Issue

I am new at android testing and I'm running into a problem. I am using RxJava and to test the UI I am using an IdlingResource. While idling resource is busy i cannot test UI.

For example: I have a button. onClick I'm doing a request. While requesting the button disables. After request the button is in enabled state. I want to test the following 3 steps:

1. Button is enabled before request
2. Button is disabled while requesting (onCLick)
3. Button is enabled when requesting ends and response message returns

I would be very very happy if you can help me in this issue...

If you need more information about my issue let me know it. I will edit my post

Solution

As I understood, you're trying to test your UI. If so, please, make sure, that you do it in right way:

1). You don't do REAL request.

Please, understand, that your test must always have same behaviour in similar situations. In other words, it must give same result, you're passing same input parameters.
Your input parameters for now:
1.1). Button is enabled before request
1.2). Button disabled during the request
1.3). Buttons enabled after request

As you can see from this list, you don't need to do a real request. It doesn't matter for you, what server will return you (error or success). You even don't need a server for this. All what you need, is just "something", that behaves like a real server. In other words, you have to mock your API client.

I suppose that you're using retrofit. If no, you have to create the interface wrapper for your client. If you're using retrofit, you just need to mock your interface.

Let's suppose, you have next interface:

public interface ApiClient{
    @GET("/items")
    Observable<MyResponse> doSomeRequest();
}

How do you usually create your API client:

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl("https://api.github.com/")
    .build();

ApiClient service = retrofit.create(ApiClient.class);

How you should do it in tests:

import static org.mockito.Mockito.*;

and in test method:

ApiClient apiMock = mock(ApiClient.class);
when(apiMock.doSomeRequest())
                .thenReturn(Observable.just(fakeResponse));

or

ApiClient apiMock = mock(ApiClient.class);
when(apiMock.doSomeRequest())
                .thenReturn(Observable.defer(new Func0<Observable<MyResponse>>() {
                        @Override
                        public Observable<MyResponse> call() {
                            try{
                                Thread.sleep(2 * 1000) //2 seconds
                            }catch(Exception e){
                                return Observable.error(e);
                            }
                            return Observable.just(fakeResponse);
                        }
                    }));

P.S. Retrofit adds .subscribeOn(Schedulers.io()) to all Observable's by default. This mocked object doesn't do it. So, please, don't forget to add .subscribeOn(Schedulers.io()) in your code, or apply it to the result of Observable.defer(...)
In code above it will look like:

when(apiMock.doSomeRequest())
     .thenReturn(Observable.defer(...).subscribeOn(Schedulers.io()));

And you should pass apiMock to Activity / Fragment which you try to test.
How to do it? See #2.

2). Use DI (dependency injection)

I will not write a lot about it.
I just recomend you to read the documentation on http://google.github.io/dagger/

And especially, how to organise project in way, when you can use real implementaions for production, and mock implementations for testing:

http://google.github.io/dagger/testing.html

In other words, when you're going to build app for usage, you provide real dependencies(in your case it will be real implementation of ApiClient), and when you're going to test some UI or business logic, you pass mock dependencies, which have behaviour specified before the test by you.

This is all, what I wanted to tell you. Hope this helped, and let me know if you have any other questions.

Answered By - Aleksandr