RenamingDelegatingContext not creating a test database

I am trying to write test cases for my app database. This is what I do in the setup method:

 @Before
    public void testCaseSetUp() {
        RenamingDelegatingContext context = new RenamingDelegatingContext(getTargetContext(), "test_");
        dbController = new DBController(context);
        dbController.open();
    }

DBController.java

public DBController(Context c) {
            context = c;
        }

        public DBController open() throws SQLException {
            dbHelper = DBHelper.getInstance(context);
            database = dbHelper.getWritableDatabase();
            return this;
        }

RenamingDelegatingContext does not create a new test database instead uses the existing db file. This is causing my test cases to fail as I already have data.