diff --git a/app/commands.py b/app/commands.py
index c76f563f3..c1bc95710 100644
--- a/app/commands.py
+++ b/app/commands.py
@@ -1,3 +1,4 @@
+import sys
 import functools
 import uuid
 from datetime import datetime, timedelta
@@ -504,7 +505,14 @@ def populate_redis_template_usage(service_id, day):
     Recalculate and replace the stats in redis for a day.
     To be used if redis data is lost for some reason.
     """
-    assert current_app.config['REDIS_ENABLED']
+    if not current_app.config['REDIS_ENABLED']:
+        current_app.logger.error('Cannot populate redis template usage - redis not enabled')
+        sys.exit(1)
+
+    # the day variable is set by click to be midnight of that day
+    start_time = get_london_midnight_in_utc(day)
+    end_time = get_london_midnight_in_utc(day + timedelta(days=1))
+
     usage = {
         str(row.template_id): row.count
         for row in db.session.query(
@@ -512,6 +520,8 @@ def populate_redis_template_usage(service_id, day):
             func.count().label('count')
         ).filter(
             Notification.service_id == service_id,
+            Notification.created_at >= start_time,
+            Notification.created_at < end_time
         ).group_by(
             Notification.template_id
         )
@@ -526,5 +536,6 @@ def populate_redis_template_usage(service_id, day):
         redis_store.set_hash_and_expire(
             key,
             usage,
-            current_app.config['EXPIRE_CACHE_EIGHT_DAYS']
+            current_app.config['EXPIRE_CACHE_EIGHT_DAYS'],
+            raise_exception=True
         )
diff --git a/tests/app/commands/__init__.py b/tests/app/commands/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/app/test_commands.py b/tests/app/commands/test_performance_platform_commands.py
similarity index 100%
rename from tests/app/test_commands.py
rename to tests/app/commands/test_performance_platform_commands.py
diff --git a/tests/app/commands/test_populate_redis.py b/tests/app/commands/test_populate_redis.py
new file mode 100644
index 000000000..25001642a
--- /dev/null
+++ b/tests/app/commands/test_populate_redis.py
@@ -0,0 +1,73 @@
+from datetime import datetime
+
+from freezegun import freeze_time
+import pytest
+
+from app.commands import populate_redis_template_usage
+
+from tests.conftest import set_config
+from tests.app.db import create_notification, create_template, create_service
+
+
+def test_populate_redis_template_usage_does_nothing_if_redis_disabled(mocker, notify_api, sample_service):
+    mock_redis = mocker.patch('app.commands.redis_store')
+    with set_config(notify_api, 'REDIS_ENABLED', False):
+        with pytest.raises(SystemExit) as exit_signal:
+            populate_redis_template_usage.callback.__wrapped__(sample_service.id, datetime.utcnow())
+
+    assert mock_redis.mock_calls == []
+    # sys.exit with nonzero exit code
+    assert exit_signal.value.code != 0
+
+
+def test_populate_redis_template_usage_does_nothing_if_no_data(mocker, notify_api, sample_service):
+    mock_redis = mocker.patch('app.commands.redis_store')
+    with set_config(notify_api, 'REDIS_ENABLED', True):
+        populate_redis_template_usage.callback.__wrapped__(sample_service.id, datetime.utcnow())
+
+    assert mock_redis.mock_calls == []
+
+
+@freeze_time('2017-06-12')
+def test_populate_redis_template_usage_only_populates_for_today(mocker, notify_api, sample_template):
+    mock_redis = mocker.patch('app.commands.redis_store')
+    # created at in utc
+    create_notification(sample_template, created_at=datetime(2017, 6, 9, 23, 0, 0))
+    create_notification(sample_template, created_at=datetime(2017, 6, 9, 23, 0, 0))
+    create_notification(sample_template, created_at=datetime(2017, 6, 10, 0, 0, 0))
+    create_notification(sample_template, created_at=datetime(2017, 6, 10, 23, 0, 0))  # actually on 11th BST
+
+    with set_config(notify_api, 'REDIS_ENABLED', True):
+        populate_redis_template_usage.callback.__wrapped__(sample_template.service_id, datetime(2017, 6, 10))
+
+    mock_redis.set_hash_and_expire.assert_called_once_with(
+        'service-{}-template-usage-2017-06-10'.format(sample_template.service_id),
+        {str(sample_template.id): 3},
+        notify_api.config['EXPIRE_CACHE_EIGHT_DAYS'],
+        raise_exception=True
+    )
+
+
+@freeze_time('2017-06-12')
+def test_populate_redis_template_usage_only_populates_for_given_service(mocker, notify_api, notify_db_session):
+    mock_redis = mocker.patch('app.commands.redis_store')
+    # created at in utc
+    s1 = create_service(service_name='a')
+    s2 = create_service(service_name='b')
+    t1 = create_template(s1)
+    t2 = create_template(s2)
+
+    create_notification(t1, created_at=datetime(2017, 6, 10))
+    create_notification(t1, created_at=datetime(2017, 6, 10))
+
+    create_notification(t2, created_at=datetime(2017, 6, 10))
+
+    with set_config(notify_api, 'REDIS_ENABLED', True):
+        populate_redis_template_usage.callback.__wrapped__(s1.id, datetime(2017, 6, 10))
+
+    mock_redis.set_hash_and_expire.assert_called_once_with(
+        'service-{}-template-usage-2017-06-10'.format(s1.id),
+        {str(t1.id): 2},
+        notify_api.config['EXPIRE_CACHE_EIGHT_DAYS'],
+        raise_exception=True
+    )