Add regression test for #719

spacy/tests/regression/test_issue719.py

@@ -0,0 +1,13 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+import pytest
+
+
+@pytest.mark.xfail
+@pytest.mark.models
+@pytest.mark.parametrize('text', ["s..."])
+def test_issue719(EN, text):
+    """Test that the token 's' is not lemmatized into empty string."""
+    tokens = EN(text)
+    assert tokens[0].lemma_ != ''