add GET /service/<id>/notifications/weekly

moved format_statistics to a new service/statistics.py file, and
refactored to share code. moved tests as well, to try and enforce
separation between the restful endpoints of rest.py and the logic/
data manipulation of statistics.py

tests/app/service/test_statistics.py

@@ -0,0 +1,131 @@
+from datetime import datetime
+import collections
+
+import pytest
+from freezegun import freeze_time
+
+from app.service.statistics import (
+    format_statistics,
+    _weeks_for_range,
+    _create_zeroed_stats_dicts,
+    format_weekly_notification_stats
+)
+
+StatsRow = collections.namedtuple('row', ('notification_type', 'status', 'count'))
+WeeklyStatsRow = collections.namedtuple('row', ('notification_type', 'status', 'week_start', 'count'))
+
+
+# email_counts and sms_counts are 3-tuple of requested, delivered, failed
+@pytest.mark.idparametrize('stats, email_counts, sms_counts', {
+    'empty': ([], [0, 0, 0], [0, 0, 0]),
+    'always_increment_requested': ([
+        StatsRow('email', 'delivered', 1),
+        StatsRow('email', 'failed', 1)
+    ], [2, 1, 1], [0, 0, 0]),
+    'dont_mix_email_and_sms': ([
+        StatsRow('email', 'delivered', 1),
+        StatsRow('sms', 'delivered', 1)
+    ], [1, 1, 0], [1, 1, 0]),
+    'convert_fail_statuses_to_failed': ([
+        StatsRow('email', 'failed', 1),
+        StatsRow('email', 'technical-failure', 1),
+        StatsRow('email', 'temporary-failure', 1),
+        StatsRow('email', 'permanent-failure', 1),
+    ], [4, 0, 4], [0, 0, 0]),
+})
+def test_format_statistics(stats, email_counts, sms_counts):
+
+    ret = format_statistics(stats)
+
+    assert ret['email'] == {
+        status: count
+        for status, count
+        in zip(['requested', 'delivered', 'failed'], email_counts)
+    }
+
+    assert ret['sms'] == {
+        status: count
+        for status, count
+        in zip(['requested', 'delivered', 'failed'], sms_counts)
+    }
+
+
+@pytest.mark.parametrize('start,end,dates', [
+    (datetime(2016, 7, 25), datetime(2016, 7, 25), [datetime(2016, 7, 25)]),
+    (datetime(2016, 7, 25), datetime(2016, 7, 28), [datetime(2016, 7, 25)]),
+    (datetime(2016, 7, 25), datetime(2016, 8, 1), [datetime(2016, 7, 25), datetime(2016, 8, 1)]),
+    (datetime(2016, 7, 25), datetime(2016, 8, 10), [
+        datetime(2016, 7, 25), datetime(2016, 8, 1), datetime(2016, 8, 8)
+    ])
+])
+def test_weeks_for_range(start, end, dates):
+    assert list(_weeks_for_range(start, end)) == dates
+
+
+def test_create_zeroed_stats_dicts():
+    assert _create_zeroed_stats_dicts() == {
+        'sms': {'requested': 0, 'delivered': 0, 'failed': 0},
+        'email': {'requested': 0, 'delivered': 0, 'failed': 0},
+    }
+
+
+@freeze_time('2016-07-28T12:00:00')
+@pytest.mark.parametrize('created_at, statistics, expected_results', [
+    # with no stats and just today, return this week's stats
+    (datetime(2016, 7, 28), [], {
+        datetime(2016, 7, 25): {
+            'sms': _stats(0, 0, 0),
+            'email': _stats(0, 0, 0)
+        }
+    }),
+    # with no stats but a service
+    (datetime(2016, 7, 14), [], {
+        datetime(2016, 7, 11): {
+            'sms': _stats(0, 0, 0),
+            'email': _stats(0, 0, 0)
+        },
+        datetime(2016, 7, 18): {
+            'sms': _stats(0, 0, 0),
+            'email': _stats(0, 0, 0)
+        },
+        datetime(2016, 7, 25): {
+            'sms': _stats(0, 0, 0),
+            'email': _stats(0, 0, 0)
+        }
+    }),
+    # two stats for same week dont re-zero each other
+    (datetime(2016, 7, 21), [
+        WeeklyStatsRow('email', 'created', datetime(2016, 7, 18), 1),
+        WeeklyStatsRow('sms', 'created', datetime(2016, 7, 18), 1),
+    ], {
+        datetime(2016, 7, 18): {
+            'sms': _stats(1, 0, 0),
+            'email': _stats(1, 0, 0)
+        },
+        datetime(2016, 7, 25): {
+            'sms': _stats(0, 0, 0),
+            'email': _stats(0, 0, 0)
+        }
+    }),
+    # two stats for same type are added together
+    (datetime(2016, 7, 21), [
+        WeeklyStatsRow('sms', 'created', datetime(2016, 7, 18), 1),
+        WeeklyStatsRow('sms', 'delivered', datetime(2016, 7, 18), 1),
+        WeeklyStatsRow('sms', 'created', datetime(2016, 7, 18), 1),
+    ], {
+        datetime(2016, 7, 18): {
+            'sms': _stats(2, 1, 0),
+            'email': _stats(0, 0, 0)
+        },
+        datetime(2016, 7, 25): {
+            'sms': _stats(1, 0, 0),
+            'email': _stats(0, 0, 0)
+        }
+    })
+])
+def test_format_weekly_notification_stats(statistics, created_at, expected_results):
+    assert format_weekly_notification_stats(statistics, created_at) == expected_results
+
+
+def _stats(requested, delivered, failed):
+    return {'requested': requested, 'delivered': delivered, 'failed': failed}