From 3d8b6f47e0a869d1068dcf38ca682330c60d44b7 Mon Sep 17 00:00:00 2001
From: Jens Larsson <jenslarsson@spotify.com>
Date: Thu, 8 Sep 2016 13:50:57 +0200
Subject: [PATCH] Support parsing DATE columns from Standard SQL tables

Change-Id: I20a6fff4362e27ee35286a3538c24e37bc858faf
---
 google/cloud/_helpers.py             | 13 +++++++++++++
 google/cloud/bigquery/_helpers.py    |  8 ++++++++
 unit_tests/bigquery/test__helpers.py | 21 +++++++++++++++++++++
 unit_tests/test__helpers.py          | 12 ++++++++++++
 4 files changed, 54 insertions(+)

diff --git a/google/cloud/_helpers.py b/google/cloud/_helpers.py
index da3e689ddc5e..a190a544d987 100644
--- a/google/cloud/_helpers.py
+++ b/google/cloud/_helpers.py
@@ -379,6 +379,19 @@ def _millis_from_datetime(value):
         return _millis(value)
 
 
+def _date_from_iso8601_date(value):
+    """Convert a ISO8601 date string to native datetime date
+
+    :type value: str
+    :param value: The date string to convert
+
+    :rtype: :class:`datetime.date`
+    :returns: A datetime date object created from the string
+
+    """
+    return datetime.datetime.strptime(value, '%Y-%m-%d').date()
+
+
 def _rfc3339_to_datetime(dt_str):
     """Convert a microsecond-precision timetamp to a native datetime.
 
diff --git a/google/cloud/bigquery/_helpers.py b/google/cloud/bigquery/_helpers.py
index 222cf2579c17..a14a9053d8d4 100644
--- a/google/cloud/bigquery/_helpers.py
+++ b/google/cloud/bigquery/_helpers.py
@@ -15,6 +15,7 @@
 """Shared helper functions for BigQuery API classes."""
 
 from google.cloud._helpers import _datetime_from_microseconds
+from google.cloud._helpers import _date_from_iso8601_date
 
 
 def _not_null(value, field):
@@ -47,6 +48,12 @@ def _datetime_from_json(value, field):
         return _datetime_from_microseconds(1e6 * float(value))
 
 
+def _date_from_json(value, field):
+    """Coerce 'value' to a datetime date, if set or not nullable"""
+    if _not_null(value, field):
+        return _date_from_iso8601_date(value)
+
+
 def _record_from_json(value, field):
     """Coerce 'value' to a mapping, if set or not nullable."""
     if _not_null(value, field):
@@ -71,6 +78,7 @@ def _string_from_json(value, _):
     'FLOAT': _float_from_json,
     'BOOLEAN': _bool_from_json,
     'TIMESTAMP': _datetime_from_json,
+    'DATE': _date_from_json,
     'RECORD': _record_from_json,
     'STRING': _string_from_json,
 }
diff --git a/unit_tests/bigquery/test__helpers.py b/unit_tests/bigquery/test__helpers.py
index 8e885c31cd59..86884f3dab2e 100644
--- a/unit_tests/bigquery/test__helpers.py
+++ b/unit_tests/bigquery/test__helpers.py
@@ -135,6 +135,27 @@ def test_w_float_value(self):
             _EPOCH + datetime.timedelta(seconds=1, microseconds=234567))
 
 
+class Test_date_from_json(unittest.TestCase):
+
+    def _callFUT(self, value, field):
+        from google.cloud.bigquery._helpers import _date_from_json
+        return _date_from_json(value, field)
+
+    def test_w_none_nullable(self):
+        self.assertIsNone(self._callFUT(None, _Field('NULLABLE')))
+
+    def test_w_none_required(self):
+        with self.assertRaises(TypeError):
+            self._callFUT(None, _Field('REQUIRED'))
+
+    def test_w_string_value(self):
+        import datetime
+        coerced = self._callFUT('1987-09-22', object())
+        self.assertEqual(
+            coerced,
+            datetime.date(1987, 9, 22))
+
+
 class Test_record_from_json(unittest.TestCase):
 
     def _callFUT(self, value, field):
diff --git a/unit_tests/test__helpers.py b/unit_tests/test__helpers.py
index db25efb23c9e..62a9ce2b63a1 100644
--- a/unit_tests/test__helpers.py
+++ b/unit_tests/test__helpers.py
@@ -532,6 +532,18 @@ def test_it(self):
         self.assertEqual(self._callFUT(NOW_MICROS), NOW)
 
 
+class Test___date_from_iso8601_date(unittest.TestCase):
+
+    def _callFUT(self, value):
+        from google.cloud._helpers import _date_from_iso8601_date
+        return _date_from_iso8601_date(value)
+
+    def test_todays_date(self):
+        import datetime
+        TODAY = datetime.date.today()
+        self.assertEqual(self._callFUT(TODAY.strftime("%Y-%m-%d")), TODAY)
+
+
 class Test__rfc3339_to_datetime(unittest.TestCase):
 
     def _callFUT(self, dt_str):