Own SqLite database in android app and Null Pointer Exception [duplicate]

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• What is a Null Pointer Exception, and how do I fix it? 12 answers

I'm trying to use my own Sqlite database in my android app here is my code

private void copyDataBase() throws IOException {
  String outFileName = databasePath + databaseName+".db";


    OutputStream myOutput = new FileOutputStream(myContext.getDatabasePath(databaseName).getAbsolutePath());

    byte[] buffer = new byte[1024];
    int i, r;
    AssetManager am = myContext.getAssets();
    String fn = String.format(databaseName);
    InputStream is = am.open(databaseName);
    while ((r = is.read(buffer)) != -1)
        myOutput.write(buffer, 0, r);
    is.close();
    myOutput.flush();
    myOutput.close();

}

But when I'm trying to test it its gives me null pointer exception Here is code of mine test class

public class DatabaseHelperTest {
@Test
public void DatabaseTest() throws Exception {
    Context context = new MockContext();
    DatabaseHelper db = new DatabaseHelper(context);

db.createDataBase();


    assertEquals(db.getInfo(1), "Test");
}

}

Mine database file is in assets folder