Add failing test for bug #1375 -- no out-of-bounds error for token.nbor()

spacy/tests/regression/test_issue1375.py

@@ -0,0 +1,16 @@
+from __future__ import unicode_literals
+import pytest
+from ...vocab import Vocab
+from ...tokens.doc import Doc
+
+@pytest.mark.xfail
+def test_issue1375():
+    '''Test that token.nbor() raises IndexError for out-of-bounds access.'''
+    doc = Doc(Vocab(), words=['0', '1', '2'])
+    with pytest.raises(IndexError):
+        assert doc[0].nbor(-1)
+    assert doc[1].nbor(-1).text == '0'
+    with pytest.raises(IndexError):
+        assert doc[2].nbor(1)
+    assert doc[1].nbor(1).text == '2'
+