Added failing test case for horejsek#23

Author: FrederikP

tests/test_datetime.py

@@ -0,0 +1,15 @@
+
+import pytest
+
+from fastjsonschema import JsonSchemaException
+
+
+exc = JsonSchemaException('data must be date-time')
+@pytest.mark.parametrize('value, expected', [
+    ('', exc),
+    ('bla', exc),
+    ('2018-02-05T14:17:10.00Z', '2018-02-05T14:17:10.00Z'),
+    ('2018-02-05T14:17:10Z', '2018-02-05T14:17:10Z'),
+])
+def test_datetime(asserter, value, expected):
+    asserter({'type': 'string', 'format': 'date-time'}, value, expected)