单元测试的文件位置

Question

This is a very simple question which I cannot find a solution for. I have a quite complex Android app which uses the camera and does some manipulations to the images taken. I now want to write Unit tests for some of the functions but I cannot get a file loaded.

In an Android test project where should I paste the Image to test on and how can I load that image into a File object? I have a normal junit.framework.TestCase class that needs to send a File to an class to test on. Thanks in advance!

Answer 1

This may not be the best solution since it could bloat your project considerably. However, short of writing code to download an image in your test cases, I'm not sure what other approach there might be.

Simply, i have 'test' drawables in my resources and I load them as bitmaps, then store them somewhere on the disc to finally reference them in my tests. This is the code I use:

public File saveResourceImageToExternalStorage(Activity activity, String picFileName, int imageId)
{
    Bitmap bitmap = BitmapFactory.decodeResource(activity.getResources(), imageId);
    File picFile = null;
    OutputStream os = null;
    try
    {
        picFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), picFileName);

        picFile.createNewFile();

        os = new FileOutputStream(picFile);

        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, os);
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }
    return file;
}

You'll probably want to make that method a little more robust.

Finally, you could just stash your test images in your assets folder for your project. Then you can get them from your assets folder using getAssets() in an Activity or using the path which should be something like file:///android_asset/your_file_name.jpg

EDIT

I think a better solution, after some research, would be to add your files to the assets of your test project and use InputStream input = this.getContext().getAssets().open("file.jpg"); . You need to call this from a class that inherits from InstrumentationTestCase or, I suppose, ActivityInstrumentationTestCase2 . You can then manipulate the input stream how you need