Add strict cross-run holdout test

.github/workflows/run-group-holdout.yml

@@ -0,0 +1,47 @@
+name: Strict request-48 run-group holdout
+
+on:
+  pull_request:
+    paths:
+      - "lhcb_wct_analysis_kit/30_run_group_holdout.py"
+      - "lhcb_wct_analysis_kit/30_run_group_holdout_xrootd.py"
+      - ".github/workflows/run-group-holdout.yml"
+      - "requirements.txt"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  holdout:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 180
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install --requirement requirements.txt
+          python -m pip install xrootd fsspec-xrootd
+      - name: Run bidirectional strict holdout
+        working-directory: lhcb_wct_analysis_kit
+        run: |
+          python 30_run_group_holdout_xrootd.py --n-null 100000 --step-size "100 MB"
+      - name: Show summary
+        if: always()
+        working-directory: lhcb_wct_analysis_kit
+        run: |
+          if [ -f outputs_run_group_holdout/holdout_summary.json ]; then
+            cat outputs_run_group_holdout/holdout_summary.json
+          fi
+      - name: Upload holdout outputs
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: run-group-holdout-results
+          path: lhcb_wct_analysis_kit/outputs_run_group_holdout/
+          if-no-files-found: warn