diff --git a/core/code_systems/tests.py b/core/code_systems/tests.py
index f8564dd1f..358c8b02f 100644
--- a/core/code_systems/tests.py
+++ b/core/code_systems/tests.py
@@ -125,7 +125,7 @@ def test_validate_code_for_code_system(self):
 
     def test_validate_code_for_code_system_via_post(self):
         response = self.client.post(
-            f'/fhir/CodeSystem/$validate-code/',
+            '/fhir/CodeSystem/$validate-code/',
             data={
                 'resourceType': 'Parameters',
                 'parameter': [
diff --git a/core/value_sets/tests.py b/core/value_sets/tests.py
index 792c0a60a..e8dc914cd 100644
--- a/core/value_sets/tests.py
+++ b/core/value_sets/tests.py
@@ -387,7 +387,7 @@ def test_validate_code_globally_via_post(self):
         self.collection_v1.seed_references()
 
         response = self.client.post(
-            f'/fhir/ValueSet/$validate-code/',
+            '/fhir/ValueSet/$validate-code/',
             data={
                 'resourceType': 'Parameters',
                 'parameter': [