Move fake wandb hook to air test file (#51303)

Breaking core -> libraries dependencies.

---------

Signed-off-by: Edward Oakes <ed.nmi.oakes@gmail.com>

Author: edoakes

python/ray/_private/test_utils.py

@@ -2143,17 +2143,6 @@ def get_gcs_memory_used():
     return sum(m.values())
 
 
-def wandb_populate_run_location_hook():
-    """
-    Example external hook to populate W&B project and group env vars in
-    WandbIntegrationTest.testWandbLoggerConfig
-    """
-    from ray.air.integrations.wandb import WANDB_GROUP_ENV_VAR, WANDB_PROJECT_ENV_VAR
-
-    os.environ[WANDB_PROJECT_ENV_VAR] = "test_project"
-    os.environ[WANDB_GROUP_ENV_VAR] = "test_group"
-
-
 def safe_write_to_results_json(
     result: dict,
     default_file_name: str = "/tmp/release_test_output.json",

python/ray/air/tests/test_integration_wandb.py

@@ -100,6 +100,17 @@ def wandb_env():
         del os.environ[WANDB_ENV_VAR]
 
 
+def fake_wandb_populate_run_location_hook():
+    """Fake user-provided hook to populate W&B environment variables."""
+    os.environ[WANDB_PROJECT_ENV_VAR] = "test_project"
+    os.environ[WANDB_GROUP_ENV_VAR] = "test_group"
+
+
+FAKE_WANDB_POPULATE_RUN_LOCATION_HOOK_IMPORT_PATH = (
+    "ray.air.tests.test_integration_wandb.fake_wandb_populate_run_location_hook"
+)
+
+
 class TestWandbLogger:
     def test_wandb_logger_project_group(self, monkeypatch):
         monkeypatch.setenv(WANDB_PROJECT_ENV_VAR, "test_project_from_env_var")
@@ -211,7 +222,7 @@ def test_wandb_logger_run_location_external_hook(self, monkeypatch):
             # Project and group env vars from external hook
             monkeypatch.setenv(
                 WANDB_POPULATE_RUN_LOCATION_HOOK,
-                "ray._private.test_utils.wandb_populate_run_location_hook",
+                FAKE_WANDB_POPULATE_RUN_LOCATION_HOOK_IMPORT_PATH,
             )
             logger = WandbTestExperimentLogger(api_key="1234")
             logger.setup()