def test_resolve_ref(self):
# item has no reference attribute
b1 = Item(id='b1')
self.assertRaises(KeyError, b1.resolve_ref, 'alignment')
# has a reference attribute, but is not contained by a tier
b1.alignment = 'a1'
self.assertRaises(XigtStructureError, b1.resolve_ref, 'alignment')
# item in tier, but tier has no reference attribute
t_b = Tier(id='b', items=[b1])
self.assertRaises(KeyError, b1.resolve_ref, 'alignment')
# tier has reference attribute, but is not contained by an Igt
t_b.alignment = 'a'
self.assertRaises(XigtStructureError, b1.resolve_ref, 'alignment')
# item in IGT, but referred tier doesn't exist
igt = Igt(tiers=[t_b])
self.assertRaises(XigtStructureError, b1.resolve_ref, 'alignment')
# referred tier exists, but has no item referred by item's alignment
t_a = Tier(id='a')
igt.append(t_a)
self.assertRaises(XigtStructureError, b1.resolve_ref, 'alignment')
# referred item exists, but has no value (which resolves to '')
a1 = Item(id='a1')
t_a.append(a1)
self.assertEqual(b1.resolve_ref('alignment'), '')
# referred item has a value
a1.text = 'text'
self.assertEqual(b1.resolve_ref('alignment'), 'text')
# stored item tests
self.assertRaises(KeyError, self.i1.resolve_ref, 'alignment')
self.assertRaises(KeyError, self.i2.resolve_ref, 'alignment')
self.assertEqual(self.i_ac.resolve_ref('alignment'), 'text')
self.assertEqual(self.i_ac.resolve_ref('content'), 'te')
self.assertEqual(self.i_s.resolve_ref('segmentation'), 'xt')
self.assertEqual(self.i_t.resolve_ref('content'), 'text')
