Technology

Roboelectric and ContentResolvers/ContentProviders


Setting up Roboelectric is dead simple. However, you may find that code like the one shown below doesn’t work:

//save using a task provider
Button saveButton = (Button) activity.findViewById(id.save_button);
saveButton.performClick();

//check that task was saved
ContentResolver resolver = activity.getContentResolver();
Cursor cursor = resolver.query(//...

//fails!
assertTrue(cursor != null);

Nothing gets saved to the mock in-memory database. Your break points in the ContentProvider don’t get called.

What gives?

Register the ContentProvider

In Roboelectric, you need to manually register your content provider. The code below does the trick:

//instantiate the ContentProvider directly
TaskProvider taskProvider = new TaskProvider();
taskProvider.onCreate();

//register the ContentProvider
ShadowContentResolver.registerProvider(TaskProvider.AUTHORITY_NAME, taskProvider);

Thanks to Vardhan for the tip!

Unimplemented Methods

We’re almost there. The default mock in-memory database is pretty cool. For basic CRUD, it works pretty much like a real database except that everything is stored in memory.

However, you might find that queries don’t work. The reason is that as of 7/27/2013, Android API 16 (which is the default version Roboelectric uses) adds a new database method that Roboelectric hasn’t implemented yet.

The solution is to…implement the missing method yourself. You have two options:

  • Add the missing method directly to shadow class. (Requires that you work directly with the Roboelectric source code).
  • Create a custom class in your test and bind it at runtime to the framework. (I haven’t figure out how to do that yet in Roboelectric 2.)

The offending class is ShadowSqlLiteDatabase. Add this method and you should be good:

@Implementation
public Cursor rawQueryWithFactory (SQLiteDatabase.CursorFactory cursorFactory,
                                 String sql,
                                 String[] selectionArgs,
                                 String editTable,
                                 CancellationSignal cancellationSignal)
{
  return rawQueryWithFactory(cursorFactory,
                             sql,
                             selectionArgs,
                             editTable);
}
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s