diff --git a/devsite/requirements/test.txt b/devsite/requirements/test.txt
new file mode 100644
index 00000000..32f9bcfd
--- /dev/null
+++ b/devsite/requirements/test.txt
@@ -0,0 +1,2 @@
+# Shared testing requirements
+pytest-freezegun==0.4.2
diff --git a/tests/test_backfill.py b/tests/test_backfill.py
index 2b960a03..e765f909 100644
--- a/tests/test_backfill.py
+++ b/tests/test_backfill.py
@@ -72,6 +72,7 @@ def backfill_test_data(db):
     )
 
 
+@pytest.mark.freeze_time('2019-09-01 12:00:00')
 def test_backfill_monthly_metrics_for_site(backfill_test_data):
     """Simple coverage and data validation check for the function under test
 
diff --git a/tox.ini b/tox.ini
index 7705f477..405aae5f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,6 +29,7 @@ deps =
 	hawthorn_multisite: -r{toxinidir}/devsite/requirements/hawthorn_multisite.txt
 	juniper_community: -r{toxinidir}/devsite/requirements/juniper_community.txt
 	juniper_multisite: -r{toxinidir}/devsite/requirements/juniper_multisite.txt
+	-r{toxinidir}/devsite/requirements/test.txt
 
 whitelist_externals =
 	git