Robolectric ContentProvider testing

Question

I have noticed that every now and then there is a question about using Robolectric for testing custom ContentProviders. However, there has never been a concrete and unambiguous answer on how to do it properly. I have stumbled upon 2 different approaches:

• one saying you can simply instantiate an in-memory ContentProvider, which you can use to insert and query data (https://gist.github.com/anonymous/6139359)

• the other saying to use the ShadowContentResolver to set mock cursor data (https://groups.google.com/d/msg/robolectric/r35mMirIkTs/xJJBNXl_RgwJ)

However, I'm getting a java.lang.InstantiationException with both approaches. There have been some SO posts saying that this is due to SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java) not being overriden in Robolectric (Android + Robolectric - RuntimeException / InstantiationException in queryBuilder.query() in ContentProvider).

I guess my question is - are there any preffered workarounds that make testing ContentProviders possible. Or are there any other approaches that are better then those 2 mentioned above.

Answer 1

This is the Robolectric (v2.4) test that worked fine for me:

import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;

import org.joda.time.LocalDate;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.annotation.Config;
import org.robolectric.shadows.ShadowContentResolver;

import co.tomup.app.db.DbSchema;
import co.tomup.app.db.TomupContentProvider;
import co.tomup.app.db.model.CalendarDay;
import co.tomup.app.db.tables.CalendarDayTable;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

@Config(emulateSdk = 18)
@RunWith(RobolectricTestRunner.class)
public class CalendarDayProviderTest {

    private ContentResolver mContentResolver;
    private ShadowContentResolver mShadowContentResolver;
    private TomupContentProvider mProvider;

    @Before
    public void setup() {
        mProvider = new TomupContentProvider();
        mContentResolver = Robolectric.application.getContentResolver();
        mShadowContentResolver = Robolectric.shadowOf(mContentResolver);
        mProvider.onCreate();
        ShadowContentResolver.registerProvider(DbSchema.AUTHORITY, mProvider);
    }

    @Test
    public void testInsertAndDelete() {
        // insert
        CalendarDay calendarDay = new CalendarDay();
        calendarDay.setId(1L);
        calendarDay.setDay(new LocalDate());
        calendarDay.setMoonPhase("new");
        calendarDay.setSunrise(1);
        calendarDay.setSunset(100);
        Uri insertionId = mContentResolver.insert(CalendarDayTable.CONTENT_URI,
                calendarDay.toSQLiteContentValues());
        Cursor cursorCheck = mShadowContentResolver.query(CalendarDayTable.CONTENT_URI,
                null, null, null, null);
        while (cursorCheck.moveToNext()) {
            CalendarDay calendarDayCheck = CalendarDay.fromSQLiteCursor(cursorCheck);
            assertEquals(calendarDay, calendarDayCheck);
        }
        assertTrue(cursorCheck.getCount() > 0);
        // delete
        mShadowContentResolver.delete(insertionId,
                null, null);
        cursorCheck = mShadowContentResolver.query(CalendarDayTable.CONTENT_URI,
                null, null, null, null);
        assertTrue(cursorCheck.getCount() == 0);
    }
}