Add test for #1773

spacy/tests/regression/test_issue1773.py

@@ -0,0 +1,9 @@
+from __future__ import unicode_literals
+
+
+def test_issue1773(en_tokenizer):
+    """Test that spaces don't receive a POS but no TAG. This is the root cause
+    of the serialization issue reported in #1773."""
+    doc = en_tokenizer('\n')
+    if doc[0].pos_ == 'SPACE':
+        assert doc[0].tag_ != ""