Change representation of UTC datetime in to_iso8601_string()

Author: sdispater

pendulum/datetime.py

@@ -328,7 +328,12 @@ def to_iso8601_string(self):
 
         :rtype: str
         """
-        return self._to_string('iso8601')
+        string = self._to_string('iso8601')
+
+        if self.tz and self.tz.name == 'UTC':
+            string = string.replace('+00:00', 'Z')
+
+        return string
 
     def to_rfc822_string(self):
         """

tests/datetime/test_strings.py

@@ -4,9 +4,9 @@
 
 
 def test_to_string():
-    d = pendulum.datetime(1975, 12, 25, 0, 0, 0, 0)
+    d = pendulum.datetime(1975, 12, 25, 0, 0, 0, 0, tz='local')
     assert str(d) == d.to_iso8601_string()
-    d = pendulum.datetime(1975, 12, 25, 0, 0, 0, 123456)
+    d = pendulum.datetime(1975, 12, 25, 0, 0, 0, 123456, tz='local')
     assert str(d) == d.to_iso8601_string()
 
 
@@ -43,6 +43,11 @@ def test_to_iso8601_string():
     assert d.to_iso8601_string() == '1975-12-25T14:15:16-05:00'
 
 
+def test_to_iso8601_string_utc():
+    d = pendulum.datetime(1975, 12, 25, 14, 15, 16)
+    assert d.to_iso8601_string() == '1975-12-25T14:15:16Z'
+
+
 def test_to_iso8601_extended_string():
     d = pendulum.datetime(1975, 12, 25, 14, 15, 16, 123456, tz='local')
     assert d.to_iso8601_string() == '1975-12-25T14:15:16.123456-05:00'