'Check output for merging option \'Concatenate tables, merge rows\' by
Source position (index)'

def test_output_merge_by_ids_outer(self):

    domain = self.dataA.domain
    result = Table(domain, np.array([[0, np.nan], [1, 1], [2, 0], [np.nan, 1]]), np.array([0, 1, 2, np.nan]), np.array([[0.0, ''], [1.0, 'm2'], [np.nan, 'm3'], [np.nan, 'm4']]).astype(object))
    self.send_signal(self.widget.Inputs.data, self.dataA[:3, [0, 'cls', (-1)]])
    self.send_signal(self.widget.Inputs.extra_data, self.dataA[1:, [1, 'cls', (-2)]])
    self.widget.attr_combine_data = 'Source    position    (index)'
    self.widget.attr_combine_extra = 'Source    position    (index)'
    self.widget.controls.merging.buttons[2].click()
    self.assertTablesEqual(self.get_output(self.widget.Outputs.data), result)
