Fix date serialization (#873)

* [panoramix] -> [dashed]

* merge from caravel/master

* Updated from airbnb

* Cleaning

* Rebase with upstream/master

* merge from caravel/master

* Updated from airbnb

* Cleaning

* Manual rebase

* Last pending change to rebase

* Convert date to datetime before serialization.
Approach choosen: transform data before serialize and keep just one way to serialize

* Unit test created

* stupid error :(

* remove uneeded code and rename test

* Avoid double type checking
Test updated
note: isinstance(<datetime>, <date>) == True, check order changed

* Increase coverage

* Fix assertRaises

caravel/utils.py

@@ -4,7 +4,7 @@ from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
 
-from datetime import datetime
+from datetime import datetime, date
 import decimal
 import functools
 import json
@@ -318,6 +318,8 @@ def json_int_dttm_ser(obj):
         return val
     if isinstance(obj, datetime):
         obj = (obj - EPOCH).total_seconds() * 1000
+    elif isinstance(obj, date):
+        obj = (obj - EPOCH.date()).total_seconds() * 1000
     else:
         raise TypeError(
             "Unserializable object {} of type {}".format(obj, type(obj))

tests/utils_tests.py

@@ -0,0 +1,19 @@
+from datetime import datetime, date, timedelta
+from caravel import utils
+import unittest
+
+
+class UtilsTestCase(unittest.TestCase):
+    def test_json_int_dttm_ser(self):
+        today = date.today()
+        now = datetime.now()
+        ms = utils.json_int_dttm_ser(today)
+        deser = (utils.EPOCH + timedelta(milliseconds=ms)).date()
+        assert today == deser, "Serialization error: %s is not %s" % (str(today), str(deser))
+        ms = utils.json_int_dttm_ser(now)
+        deser = (utils.EPOCH + timedelta(milliseconds=ms))
+        assert now == deser, "Serialization error: %s is not %s" % (str(now), str(deser))
+
+        with self.assertRaises(TypeError):
+            utils.json_int_dttm_ser("this is not a date")
+