diff --git a/reflex/config.py b/reflex/config.py
index c3c1c23b7..bff7bca1b 100644
--- a/reflex/config.py
+++ b/reflex/config.py
@@ -494,6 +494,12 @@ class EnvironmentVariables:
     # Whether to run app harness tests in headless mode.
     APP_HARNESS_HEADLESS: EnvVar[bool] = env_var(False)
 
+    # Which app harness driver to use.
+    APP_HARNESS_DRIVER: EnvVar[str] = env_var("Chrome")
+
+    # Arguments to pass to the app harness driver.
+    APP_HARNESS_DRIVER_ARGS: EnvVar[str] = env_var("")
+
 
 environment = EnvironmentVariables()
 
diff --git a/reflex/testing.py b/reflex/testing.py
index 5a4f4e1db..3a88fb595 100644
--- a/reflex/testing.py
+++ b/reflex/testing.py
@@ -620,7 +620,7 @@ class AppHarness:
         if environment.APP_HARNESS_HEADLESS.get:
             want_headless = True
         if driver_clz is None:
-            requested_driver = os.environ.get("APP_HARNESS_DRIVER", "Chrome")
+            requested_driver = environment.APP_HARNESS_DRIVER.get
             driver_clz = getattr(webdriver, requested_driver)
             if driver_options is None:
                 driver_options = getattr(webdriver, f"{requested_driver}Options")()
@@ -642,7 +642,7 @@ class AppHarness:
                 driver_options.add_argument("headless")
         if driver_options is None:
             raise RuntimeError(f"Could not determine options for {driver_clz}")
-        if args := os.environ.get("APP_HARNESS_DRIVER_ARGS"):
+        if args := environment.APP_HARNESS_DRIVER_ARGS.get:
             for arg in args.split(","):
                 driver_options.add_argument(arg)
         if driver_option_args is not None: