blue_diamond blue_diamond - 4 months ago 20
Android Question

Why in a test class that extends AndroidTestCase, does getContext() return null?

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);
}
}


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();
}


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)
...


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

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

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

Answer

For accessing a context you can:

  1. Extend from InstrumentationTestCase and then call getInstrumentation().getContext()
  2. Use reflection to access a private member

You can see code samples at this answer