Android + Robolectric - 在 ContentProvider 中的 queryBuilder.query() 抛出 RuntimeException / InstantiationException

Question

我在ContentProvider上做了大约十个测试，这些测试只使用SQLite；除了通过Content Provider的query()方法中的queryBuilder.query()传递的两个测试未能通过外，其余测试均已通过。

被测试的方法在实际应用程序中有效！

这是在API 17 r2和RoboLectric下进行的： robolectric-2.0-alpha-3-20130417.013705-46-jar-with-dependencies.jar

@Override
public Cursor query(Uri uri, String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {
    Log.d(Constants.TAG, "MyContentProvider.query()");
    switch(matcher.match(uri)) {
    case ITEM: // OK
        selection = "_id = ?";
        selectionArgs = new String[]{ Long.toString(ContentUris.parseId(uri)) };
    case ITEMS: // OK
        break;
    default:
        throw new IllegalArgumentException("Did not recognize URI " + uri);
    }
    // build the query with SQLiteQueryBuilder
    SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();
    qBuilder.setTables(TABLE_NAME);

    // query the database and get result in cursor
    final SQLiteDatabase db = mDatabase.getReadableDatabase();
    Cursor resultCursor = qBuilder.query(db,    // Line 112 in trace
            projection, selection, selectionArgs, null, null, sortOrder,
            null);
    resultCursor.setNotificationUri(getContext().getContentResolver(), uri);
    return resultCursor;
}

以下是跟踪信息：

java.lang.RuntimeException: java.lang.InstantiationException
    at org.robolectric.bytecode.ShadowWrangler.createShadowFor(ShadowWrangler.java:300)
    at org.robolectric.bytecode.ShadowWrangler.initializing(ShadowWrangler.java:74)
    at org.robolectric.bytecode.RobolectricInternals.initializing(RobolectricInternals.java:90)
    at android.database.sqlite.SQLiteQuery.$$robo$init(SQLiteQuery.java)
    at android.database.sqlite.SQLiteClosable.<init>(SQLiteClosable.java:26)
    at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:41)
    at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
    at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
    at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
    at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:400)
    at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:333)
    at com.example.readingsprovider.ReadingsContentProvider.query(ReadingsContentProvider.java:112)
    at com.example.readingsprovider.test.ContentProviderTest.testUpdateMultipleWithoutWhere(ContentProviderTest.java:110)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:267)
    at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:202)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.InstantiationException
    at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at java.lang.Class.newInstance0(Class.java:357)
    at java.lang.Class.newInstance(Class.java:310)
    at org.robolectric.bytecode.ShadowWrangler.createShadowFor(ShadowWrangler.java:293)
    at org.robolectric.bytecode.ShadowWrangler.initializing(ShadowWrangler.java:74)
    at org.robolectric.bytecode.RobolectricInternals.initializing(RobolectricInternals.java:90)
    at android.database.sqlite.SQLiteQuery.$$robo$init(SQLiteQuery.java)
    at android.database.sqlite.SQLiteClosable.<init>(SQLiteClosable.java:26)
    at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:41)
    at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
    at android.database.sqlite.SQLiteDirectCursorDriver.$$robo$$SQLiteDirectCursorDriver_7ac1_query(SQLiteDirectCursorDriver.java:44)
    at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java)
    at android.database.sqlite.SQLiteDatabase.$$robo$$SQLiteDatabase_ab15_rawQueryWithFactory(SQLiteDatabase.java:1314)
    at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java)
    at android.database.sqlite.SQLiteQueryBuilder.$$robo$$SQLiteQueryBuilder_ba4d_query(SQLiteQueryBuilder.java:400)
    at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java)
    at android.database.sqlite.SQLiteQueryBuilder.$$robo$$SQLiteQueryBuilder_ba4d_query(SQLiteQueryBuilder.java:333)
    at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java)
    at com.example.readingsprovider.ReadingsContentProvider.query(ReadingsContentProvider.java:112)
    at com.example.readingsprovider.test.ContentProviderTest.testUpdateMultipleWithoutWhere(ContentProviderTest.java:110)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    ... 21 more

请问这是Robolectric的限制还是我的问题？谢谢！

另外，如果反射API在InstantiationException消息中加入失败的类名，那不是很好吗？

- idarwin

Answer 1

我曾经在我的项目中遇到了同样的问题，最终在查找资料和参考U Avalos的回答后解决了这个问题。

1. 创建自定义SQLiteShadow

@Implements(value = SQLiteDatabase.class, inheritImplementationMethods = true)
public class CustomSQLiteShadow extends ShadowSQLiteDatabase {

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

2. 给你的测试添加@Config注解

为了使用自定义的阴影类，你可以在robolectric2中使用@Config注解。

@RunWith(RobolectricTestRunner.class)
@Config( shadows = {CustomSQLiteShadow.class})
public class ContentProviderTest {

Reference

http://robolectric.blogspot.co.at/2013/05/configuring-robolectric-20.html

- Sukram

Answer 2

Android API 16引入了这个新方法（mtholdefer提到）：

public Cursor rawQueryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, String sql, String[] selectionArgs, String editTable, CancellationSignal cancellationSignal)

截至2013年7月25日，roboelectric尚未实现此方法。但是，它实现了一种不使用CancellationSignal的类似方法。将此方法添加到ShadowSqlLiteDatabase中，问题就得以解决。

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

（是的，你需要将roboelectric作为子模块。）

- U Avalos

---

实际上，您应该能够在测试中创建自定义的 shadow 类并在运行时绑定它。然而，我还没有弄清楚如何在 Roboelectric 2 中实现这一点。 - U Avalos

Answer 3

我遇到了类似的问题，我认为问题在于Robolectric不支持SQLiteQueryBuilder。你可以在这里阅读更多相关信息。基本上，SQLiteQueryBuilder使用的rawQueryWithFactor()方法没有在ShadowSQLiteDatabase中被覆盖。因此，cusor返回为空。

我刚刚开始通过SQLiteDatabaseInstance.query实例化我的游标，并且在与Robolectric一起使用时完美运行。祝你好运，如果你找到更优雅的解决方案，请告诉我，这样我也可以测试我的queryBuilders！

- mtholdefer

---

我遇到了同样的问题。你介意分享一下代码片段吗？如果我理解正确，你重写了Android类以适应单元测试？ - U Avalos

转念一想，你为什么不直接实现那个方法呢？我正在使用从GitHub分叉出来的Roboelectric 2，在实现了缺失的方法后，它就可以工作了。 - U Avalos

不，我在测试类中创建了游标，并跳过了使用queryBuilder的代码测试。那只是一个小方法，所以不值得麻烦。但如果你经常使用它，实现rawQueryWithFactory肯定是值得的。 - mtholdefer