fix: skip PyTorch-dependent tests in sanity mode

Author: V2arK

tests/conftest.py

@@ -3,11 +3,22 @@
 
 os.environ["TOKENIZERS_PARALLELISM"] = "false"
 
+# Tests that require PyTorch at import time -- skip during sanity runs
+# where PyTorch is not installed.
+_PYTORCH_TEST_FILES = ["test_backend.py", "test_helpers.py", "test_server.py"]
+
+collect_ignore = []
+
 
 def pytest_addoption(parser):
     parser.addoption("--sanity", action="store_true", help="Run sanity tests (exclude 'gpu' tests)")
 
 
+def pytest_configure(config):
+    if config.getoption("--sanity", default=False):
+        collect_ignore.extend(_PYTORCH_TEST_FILES)
+
+
 def pytest_collection_modifyitems(config, items):
     if config.getoption("--sanity"):
         skip_gpu = pytest.mark.skip(reason="Skipping GPU tests for sanity run")