migrate APP_HARNESS_HEADLESS to new env var system

reflex/config.py

@@ -491,6 +491,9 @@ class EnvironmentVariables:
     # If this env var is set to "yes", App.compile will be a no-op
     REFLEX_SKIP_COMPILE: EnvVar[bool] = env_var(False, internal=True)
 
+    # Whether to run app harness tests in headless mode.
+    APP_HARNESS_HEADLESS: EnvVar[bool] = env_var(False)
+
 
 environment = EnvironmentVariables()
 

reflex/testing.py

@@ -617,7 +617,7 @@ class AppHarness:
         if self.frontend_url is None:
             raise RuntimeError("Frontend is not running.")
         want_headless = False
-        if os.environ.get("APP_HARNESS_HEADLESS"):
+        if environment.APP_HARNESS_HEADLESS.get:
             want_headless = True
         if driver_clz is None:
             requested_driver = os.environ.get("APP_HARNESS_DRIVER", "Chrome")

tests/integration/conftest.py

@@ -6,6 +6,7 @@ from pathlib import Path
 
 import pytest
 
+from reflex.config import environment
 from reflex.testing import AppHarness, AppHarnessProd
 
 DISPLAY = None
@@ -21,7 +22,7 @@ def xvfb():
     Yields:
         the pyvirtualdisplay object that the browser will be open on
     """
-    if os.environ.get("GITHUB_ACTIONS") and not os.environ.get("APP_HARNESS_HEADLESS"):
+    if os.environ.get("GITHUB_ACTIONS") and not environment.APP_HARNESS_HEADLESS.get:
         from pyvirtualdisplay.smartdisplay import (  # pyright: ignore [reportMissingImports]
             SmartDisplay,
         )