def METHOD_NAME(self):
    # Alter collagen to have a "type" variable value with no members
    gvar = self.collagen.domain.class_var
    svfilter = Orange.data.filter.SameValue(gvar, gvar.values[0], negate=True)
    collagen = svfilter(self.collagen)
    self.send_signal("Data", collagen)
    self.widget.group_var = gvar
    self.widget.grouping_changed()
    out = self.get_output("Averages")
    self.assertEqual(out.X.shape[0], len(gvar.values) - 1)