Robolectric测试

Question

我注意到，时不时会有一个关于使用Robolectric测试自定义ContentProviders的问题。然而，对于如何恰当地做到这一点，从来没有一个具体和明确的答案。我偶然发现了两种不同的方法：

• 一种说法是，您可以简单地实例化内存中的ContentProvider，您可以使用它来插入和查询数据(https://gist.github.com/anonymous/6139359)。
• 另一种说法是使用ShadowContentResolver设置模拟游标数据(RgwJ)。

但是，我得到的是两种方法的java.lang.InstantiationException。有一些这样的帖子说，这是因为SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java)没有在Robolectric (Android + Robolectric - RuntimeException / InstantiationException in queryBuilder.query() in ContentProvider)中被超越。

我想我的问题是-是否有任何预先提出的解决办法使测试ContentProviders成为可能。或者还有比上面提到的两种方法更好的方法。

Answer 1

这是对我来说很好的Robolectric (v2.4)测试：

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);
    }
}

Answer 2

您所要做的就是在测试之前设置ShadowContentResolver，因此它将正确地将ContentProvider的权限与ContentProvider本身关联起来。下面是一个示例：

ShadowContentResolver.registerProvider(
        "com.example.provider",    //authority of your provider
        contentProvider    //instance of your ContentProvider (you can just use default constructor)    
);

最简单的方法是将这些内容放入一些@Before注释的设置方法中。但是，更正确的方法(因此从长远来看更好)是将其应用到TestApplication#onCreate方法中，因此应用程序中的所有测试都将使用此配置。

Answer 3

使用RoboElectric4.2，这对我起了作用：

@RunWith(RobolectricTestRunner.class)
public class MyContentProviderTest {

    private ContentResolver contentResolver;
    private MyRepository repository;

    @Before
    public void setup() {
        repository = mock(MyRepository.class);
        contentResolver = ApplicationProvider.getApplicationContext().getContentResolver();

        ProviderInfo info = new ProviderInfo();
        info.authority = "my.authority";
        info.grantUriPermissions = true;
        ContentProviderController<MediaContentProvider> controller = Robolectric
                .buildContentProvider(MyContentProvider.class)
                .create(info);

        MyContentProvider provider = controller.get();
        // Method in my ContentProvider that allows to override
        // the repository it uses
        provider.setRepository(repository);
    }

    @Test
    public void testQuery() {

        // setup expectations in mockito
        when(repository.getAll()).thenReturn(...);

        try (Cursor cursor = contentResolver.query(SOME_URI, null, null, null, null)) {
            // test cursor contents here
        }

    }
}