diff --git a/lib/mobile_app_backend/mapbox_token_rotator.ex b/lib/mobile_app_backend/mapbox_token_rotator.ex
index 531eb315..3d468f77 100644
--- a/lib/mobile_app_backend/mapbox_token_rotator.ex
+++ b/lib/mobile_app_backend/mapbox_token_rotator.ex
@@ -1,6 +1,14 @@
+defmodule MobileAppBackend.MapboxTokenRotator.Behaviour do
+  @callback get_public_token() :: String.t()
+end
+
 defmodule MobileAppBackend.MapboxTokenRotator do
   use GenServer
 
+  alias MobileAppBackend.MapboxTokenRotator
+
+  @behaviour MapboxTokenRotator.Behaviour
+
   defmodule State do
     defstruct [:primary_token, :username, :current_public_token, :expire_ms, :rotate_ms]
   end
@@ -10,7 +18,7 @@ defmodule MobileAppBackend.MapboxTokenRotator do
     GenServer.start_link(__MODULE__, nil, name: server_name)
   end
 
-  @spec get_public_token(GenServer.server()) :: String.t()
+  @impl MapboxTokenRotator.Behaviour
   def get_public_token(server \\ __MODULE__) do
     GenServer.call(server, :get_public_token)
   end
diff --git a/lib/mobile_app_backend_web/controllers/client_config_controller.ex b/lib/mobile_app_backend_web/controllers/client_config_controller.ex
index 33efd205..d791d1fb 100644
--- a/lib/mobile_app_backend_web/controllers/client_config_controller.ex
+++ b/lib/mobile_app_backend_web/controllers/client_config_controller.ex
@@ -6,8 +6,11 @@ defmodule MobileAppBackendWeb.ClientConfigController do
 
   @spec config(Plug.Conn.t(), any()) :: Plug.Conn.t()
   def config(conn, _params) do
+    token_rotator_module =
+      Application.get_env(:mobile_app_backend, MapboxTokenRotator, MapboxTokenRotator)
+
     client_config = %ClientConfig{
-      mapbox_public_token: MapboxTokenRotator.get_public_token()
+      mapbox_public_token: token_rotator_module.get_public_token()
     }
 
     json(conn, client_config)
diff --git a/test/mobile_app_backend/mapbox_token_rotator_test.exs b/test/mobile_app_backend/mapbox_token_rotator_test.exs
index 0218a726..5d122051 100644
--- a/test/mobile_app_backend/mapbox_token_rotator_test.exs
+++ b/test/mobile_app_backend/mapbox_token_rotator_test.exs
@@ -137,6 +137,6 @@ defmodule MobileAppBackend.MapboxTokenRotatorTest do
 
     actual_interval = second_token_time - first_token_time
 
-    assert (actual_interval - refresh_interval) in -5..5
+    assert (actual_interval - refresh_interval) in -50..50
   end
 end
diff --git a/test/mobile_app_backend_web/controllers/client_config_controller_test.exs b/test/mobile_app_backend_web/controllers/client_config_controller_test.exs
index e785ca95..fcabb1cb 100644
--- a/test/mobile_app_backend_web/controllers/client_config_controller_test.exs
+++ b/test/mobile_app_backend_web/controllers/client_config_controller_test.exs
@@ -3,22 +3,24 @@ defmodule MobileAppBackendWeb.ClientControllerTest do
   use MobileAppBackendWeb.ConnCase
   import Test.Support.Helpers
   import Mox
-  alias MobileAppBackend.MapboxTokenRotator
 
   describe "GET /api/protected/config" do
     setup do
       verify_on_exit!()
 
-      reassign_env(:mobile_app_backend, MobileAppBackend.ClientConfig,
-        mapbox_public_token: "fake_mapbox_token"
+      reassign_env(
+        :mobile_app_backend,
+        MobileAppBackend.MapboxTokenRotator,
+        MapboxTokenRotatorMock
       )
 
-      MapboxTokenRotator |> Process.whereis() |> Process.exit(:refresh_config)
-
       :ok
     end
 
     test "returns config", %{conn: conn} do
+      MapboxTokenRotatorMock
+      |> expect(:get_public_token, fn -> "fake_mapbox_token" end)
+
       conn = get(conn, "/api/protected/config")
       %{"mapbox_public_token" => "fake_mapbox_token"} = json_response(conn, 200)
     end
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 170b17b6..116f4f5f 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -1,14 +1,15 @@
-Mox.defmock(AlertsStoreMock, for: MBTAV3API.Store)
 Mox.defmock(AlertsPubSubMock, for: MobileAppBackend.Alerts.PubSub.Behaviour)
+Mox.defmock(AlertsStoreMock, for: MBTAV3API.Store)
 Mox.defmock(GlobalDataCacheMock, for: MobileAppBackend.GlobalDataCache)
-Mox.defmock(RepositoryMock, for: MBTAV3API.Repository)
-Mox.defmock(StaticInstanceMock, for: MBTAV3API.Stream.StaticInstance)
+Mox.defmock(MapboxTokenRotatorMock, for: MobileAppBackend.MapboxTokenRotator.Behaviour)
 Mox.defmock(MobileAppBackend.HTTPMock, for: MobileAppBackend.HTTP)
-Mox.defmock(StreamSubscriberMock, for: MobileAppBackend.Predictions.StreamSubscriber)
 Mox.defmock(PredictionsPubSubMock, for: MobileAppBackend.Predictions.PubSub.Behaviour)
 Mox.defmock(PredictionsStoreMock, for: MBTAV3API.Store)
-Mox.defmock(VehiclesStoreMock, for: MBTAV3API.Store)
+Mox.defmock(RepositoryMock, for: MBTAV3API.Repository)
+Mox.defmock(StaticInstanceMock, for: MBTAV3API.Stream.StaticInstance)
+Mox.defmock(StreamSubscriberMock, for: MobileAppBackend.Predictions.StreamSubscriber)
 Mox.defmock(VehiclesPubSubMock, for: MobileAppBackend.Vehicles.PubSub.Behaviour)
+Mox.defmock(VehiclesStoreMock, for: MBTAV3API.Store)
 
 Application.put_env(:mobile_app_backend, MobileAppBackend.HTTP, MobileAppBackend.HTTPMock)