如何为 AlertDialog 进行 Robolectric 测试

Question

I am new to robolectric and I am trying to make a test for a button that creates an AlertDialog. When the button is clicked, an AlertDialog is made with a positive button that I want to click using Robolectric, and test if it launches an activity. Here is the code for the button:

newUserButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            AlertDialog.Builder builder = new AlertDialog.Builder(StartActivity.this);
            builder.setTitle(context.getResources().getString(R.string.start_title_message))
                    .setMessage(getResources().getString(R.string.start_dialog_message));
            builder.setPositiveButton(getString(R.string.start_confirm_message), new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    startActivityForResult(new Intent(StartActivity.this, AvatarRoomActivity.class), 0);
                }
            });
            builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.dismiss();
                }
            });
            AlertDialog dialog = builder.create();
            ColorDrawable drawable = new ColorDrawable(Color.WHITE);
            drawable.setAlpha(200);
            dialog.getWindow().setBackgroundDrawable(drawable);
            dialog.show();
        }
    });

Does anyone know how I can test clicking the positive button, then launching AvatarRoomActivity? Thanks in advance and hope to hear from someone soon.

Answer 1

I came across this problem today, and exposing a private function just for testing is not advised.

Robolectric provides a ShadowAlertDialog , which can detect a shown Dialog or AlertDialog .

//get all shown dialogs    
ShadowAlertDialog.getShownDialogs()

//get single dialog  
(ShadowAlertDialog.getLatestDialog() as android.support.v7.app.AlertDialog)
    .getButton(AlertDialog.BUTTON_POSITIVE)
    .performClick()

//Continue the test

Answer 2

Let's forget the newUserButton for a while. It is not relevant to the problem.

You will need to expose the AlertDialog object so that it is accessible in unit test code. So I assume you activity have such a method in StartActivity:

AlertDialog showDialog() {

    AlertDialog.Builder builder = new AlertDialog.Builder(StartActivity.this);
    builder.setTitle("This is title")
            .setMessage("Dialog Message");
    builder.setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            startActivityForResult(new Intent(this, AvatarRoomActivity.class), 0);
        }
    });
    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            dialog.dismiss();
        }
    });
    AlertDialog dialog = builder.create();
    dialog.show();

    return dialog;

}

then the click event of newUserButton just invoke this method.

Then we have the test case like this:

@Test
public void testLaunchAvatarRoomWhenConfirm() {

    StartActivity startActivity = Robolectric.buildActivity(StartActivity.class).create().get();

    AlertDialog dialog = startActivity.showDialog();

    // Key part 1 : simulate button click in unit test
    Button confirm = dialog.getButton(Dialog.BUTTON_POSITIVE);
    confirm.performClick();

    // Key part 2 : Check that startActivityForResult is invoke
    ShadowActivity shadowActivity = shadowOf(startActivity);
    ShadowActivity.IntentForResult intentForResult = shadowActivity.getNextStartedActivityForResult();

    // assert that the proper request to start activity is sent
    ComponentName nextActivity = intentForResult.intent.getComponent();
    assertEquals(".AvatarRoomActivity", nextActivity.getShortClassName());

}

This test method verify that when the dialog's positive button is clicked, startActivityForResult is invoked with proper activity class name.

So the remaining problem is how do we ensure the activity is really resolved and launched. Normally I would stop at this point for testing of alert dialog actions. Whether the intent can be resolved and start activity property is out of the scope of this particular test case.