CI: experiment — disable xdist, add -v for unbuffered test output

.ci/docker/requirements-ci.txt

@@ -11,6 +11,7 @@ zstd==1.5.5.1
 pandas>=2.2.2; python_version >= '3.10'
 pytest==7.2.0
 pytest-cov==4.1.0
+pytest-timeout==2.2.0
 expecttest==0.1.6
 hypothesis==6.84.2
 parameterized==0.9.0

.ci/scripts/unittest-macos-cmake.sh

@@ -12,8 +12,13 @@ set -eux
 export TORCHINDUCTOR_CACHE_DIR="$(mktemp -d "${RUNNER_TEMP:-/tmp}/torchinductor_cache_XXXXXX")"
 trap 'rm -rf "${TORCHINDUCTOR_CACHE_DIR}"' EXIT
 
-# Run pytest with coverage
-${CONDA_RUN} pytest -n auto --cov=./ --cov-report=xml
+# EXPERIMENT: run without xdist entirely so output is unbuffered and each test
+# name prints immediately (with -n 1, xdist still buffers all output in a
+# worker process, hiding which test is hanging). -v prints test names as they
+# start; faulthandler_timeout dumps threads if a single test stalls.
+${CONDA_RUN} pytest -p no:xdist -v --cov=./ --cov-report=xml \
+  --timeout=1500 --timeout-method=thread \
+  -o faulthandler_timeout=180
 # Run gtest
 LLVM_PROFDATA="xcrun llvm-profdata" LLVM_COV="xcrun llvm-cov" \
 ${CONDA_RUN} test/run_oss_cpp_tests.sh

.github/workflows/_unittest.yml

@@ -49,6 +49,7 @@ jobs:
       python-version: '3.11'
       submodules: 'recursive'
       ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+      timeout: 90
       script: |
         set -eux
         # This is needed to get the prebuilt PyTorch wheel from S3