Fix GPU tests (token + single-process) (#294)

Author: anton-l

.github/workflows/push_tests.yml

@@ -46,5 +46,7 @@ jobs:
         python utils/print_env.py
 
     - name: Run all (incl. slow) tests on GPU
+      env:
+        HF_API_TOKEN: ${{ secrets.HF_API_TOKEN }}
       run: |
-        python -m pytest -n 2 --max-worker-restart=0 --dist=loadfile -s tests/
+        python -m pytest -n 1 --max-worker-restart=0 --dist=loadfile -s tests/