diff --git a/app/middleware.py b/app/middleware.py
index c96e520..7e3d20d 100644
--- a/app/middleware.py
+++ b/app/middleware.py
@@ -11,6 +11,8 @@ logger = logging.getLogger(__name__)
 class PatchMalformedJsonMiddleware(BaseHTTPMiddleware):
     # see oscar.krause/fastapi-dls#1
 
+    REGEX = '(\"mac_address_list\"\:\s?\[)([\w\d])'
+
     def __init__(self, app, enabled: bool):
         super().__init__(app)
         self.enabled = enabled
@@ -28,8 +30,7 @@ class PatchMalformedJsonMiddleware(BaseHTTPMiddleware):
                 body = body.replace('\t', '')
                 body = body.replace('\n', '')
 
-                regex = '(\"mac_address_list\"\:\s?\[)([\w\d])'
-                s = re.sub(regex, r'\1"\2', body)
+                s = re.sub(PatchMalformedJsonMiddleware.REGEX, r'\1"\2', body)
                 logger.debug(f'Fixed JSON: "{s}"')
                 s = json.loads(s)  # ensure json is now valid
 
diff --git a/test/main.py b/test/main.py
index 3aa229b..2e70558 100644
--- a/test/main.py
+++ b/test/main.py
@@ -111,11 +111,11 @@ def test_auth_v1_origin():
 
 def test_auth_v1_origin_malformed_json():  # see oscar.krause/fastapi-dls#1
     import re
+    from middleware import PatchMalformedJsonMiddleware
 
     # test regex (temporary, until this section is merged into main.py
-    json_test = '{"environment": {"fingerprint": {"mac_address_list": [ff:ff:ff:ff:ff:ff"]}}'
-    regex = '(\"mac_address_list\"\:\s?\[)([\w\d])'
-    replaced = re.sub(regex, r'\1"\2', json_test)
+    body = '{"environment": {"fingerprint": {"mac_address_list": [ff:ff:ff:ff:ff:ff"]}}'
+    replaced = re.sub(PatchMalformedJsonMiddleware.REGEX, r'\1"\2', body)
     assert replaced == '{"environment": {"fingerprint": {"mac_address_list": ["ff:ff:ff:ff:ff:ff"]}}'