def METHOD_NAME(
    make_napari_viewer,
    tmp_plugin: DynamicPlugin,
):
    """Checks that sample data callback `_add_sample` shows all readers."""
    tmp2 = tmp_plugin.spawn(register=True)
    @tmp_plugin.contribute.reader(filename_patterns=['*.fake'])
    def _(path):
        ...
    @tmp2.contribute.reader(filename_patterns=['*.fake'])
    def _(path):
        ...
    my_sample = SampleDataURI(
        key='tmp-sample',
        display_name='Temp Sample',
        uri='some-path/some-file.fake',
    )
    tmp_plugin.manifest.contributions.sample_data = [my_sample]
    from napari._qt.dialogs.qt_reader_dialog import QtReaderDialog
    viewer = make_napari_viewer()
    sample_action = viewer.window.file_menu.open_sample_menu.actions()[0]
    with mock.patch(
        'napari._qt.dialogs.qt_reader_dialog.prepare_remaining_readers'
    ) as mock_prepare_readers, mock.patch.object(
        QtReaderDialog, 'get_user_choices', return_value=(None, None)
    ):
        sample_action.trigger()
    # Ensure that `prepare_remaining_readers` called with `plugin_name=None`
    mock_prepare_readers.assert_called_once_with(
        ['some-path/some-file.fake'], None, None
    )