为什么在扩展 AndroidTestCase 的测试类中，getContext() 是否返回 null? [英] Why in a test class that extends AndroidTestCase, does getContext() return null?

问题描述

我有自己的 SQLiteOpenHelper 如下:

I have my own SQLiteOpenHelper as follow :

public class MyOpenHelper extends SQLiteOpenHelper {

  public static final int DB_VERSION = 1;
  public static final String DB_NAME = "dbname";

  public MyOpenHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
  }

  @Override
  public void onCreate(SQLiteDatabase sqLiteDatabase) {
    /* My create code */
  }

  @Override
  public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
    /* My upgrade code */
  }

  @Override
  public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);
  }
}

还有我的 AndroidTestCase 测试类:

And my AndroidTestCase test class :

public class MyOpenHelperTest extends AndroidTestCase {

  protected MyOpenHelper myOpenHelper;
  protected SQLiteDatabase sqLiteDatabase;

  public MyBdOpenHelperTest() {
    super();

    assertNotNull( getContext() );

    this.myBdOpenHelper = new MyOpenHelper(getContext());
    this.sqLiteDatabase = this.myOpenHelper.getReadableDatabase();
}

然后当我执行这个测试类时，我得到了这个错误堆栈跟踪:

Then when I execute this test class, i've got this error stack trace :

junit.framework.AssertionFailedError: Exception in constructor:  
testAndroidTestCaseSetupProperly (junit.framework.AssertionFailedError
at fr.power.db.MyOpenHelperTest.<init>(MyOpenHelperTest.java:21)
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at junit.runner.BaseTestRunner.getTest(BaseTestRunner.java:118)
...

为什么 getContext() 返回空上下文?因为我在一个非活动测试用例中?

Why does getContext() returns a null context ? Because I'm in a non Activity test case ?

我应该在关于使用 SQLiteOpenHelper 的活动的 ActivityUnitTestCase 中测试我的 SQLiteOpenHelper 吗?

Should I test my SQLiteOpenHelper in an ActivityUnitTestCase about an activity that uses the SQLiteOpenHelper ?

有人可以帮忙吗?我只想测试我的 SQLiteOpenHelper 以确保数据库创建良好.

Someone can give some help please ? I just want to test my SQLiteOpenHelper to be sure the database is well created.

推荐答案

要访问 context，您可以:

1. 从 InstrumentationTestCase 扩展，然后调用 getInstrumentation().getContext()
2. 使用反射访问私有成员

您可以在这个答案中查看代码示例

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