Add weird is_iso_date tests #14

These are non-valid ISO dates but we do not validate fully
just a surface validation using a regex.

This captures the weird cases we accept.

Reference: #14
Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Co-authored-by: Frank Dana <ferdnyc@gmail.com>

Author: pombredanne

tests/test_saneyaml.py

@@ -149,6 +149,9 @@ def test_is_iso_date(self):
         assert not saneyaml.is_iso_date('1994-01-1')
         assert not saneyaml.is_iso_date('1994-1-1')
         assert not saneyaml.is_iso_date('193')
+        # Hey, nothing's perfect
+        assert saneyaml.is_iso_date('2003-02-29')
+        assert saneyaml.is_iso_date('2004-01-35')
 
 
 safe_chars = re.compile(r'[\W_]', re.MULTILINE)