Unit Testing and Android DownloadManager

Question

I would like to unit test a class that makes use of the Android DownloadManager service, but I'm not sure how to go about doing it. Should I actually use the DownloadManager service or is there some way I can mock it up? I would rather not have my test call an external web server. Is there an existing testing library I can use for this?

Answer 1

1. This solution use Robolectric

One important thing to know is that the count of Download Manager requests starts at -1. So if you enqueue a request, the request count gonna be 0.

2. Mock your DownloadManager object

3. Write your test

   public void shouldEnqueueRequest() {
   //...
   
   //...
   
   verify(downloadManager, times(1)).enqueue(anyObject());
   //Is the DownloadManager empty
   assertThat(shadowOf(downloadManager).getRequestCount(), greaterThan(-1));
   //Get the request from the DownloadManager
   ShadowRequest realRequest = shadowOf(shadowOf(downloadManager).getRequest(0));
   assertThat(realRequest, notNullValue());
   assertThat(realRequest.getDescription(), equalTo("Your description"));
   assertThat(realRequest.getTitle(), equalTo(APP_NAME));
   }