Implement Storage that will wrap Realm

[abdrasulov]

The Issue

Using Realm directly makes harder to write automated tests. The current solution with Realm in memory requires appContext to run tests. That is why we have to write unit test as android Instrumented test. I've came to that instrumented tests are good for UI testing, not for unit testing. We cannot use tools like Powermock there. In addition assertion blocks in tests look complicated.

Solution

Add a new class (singleton?) Storage. Realm clients will use this object instead of Realm. It will have concrete methods for retrieving and storing objects. As a result the current realm clients will dependent on Storage object. We can mock Storage without any problem in unit tests without appContext. So we will be able to write simple unit tests.

[abdrasulov]

This issue is no longer relevant since Realm has been replaced with Room