gha: warm up uv cache by building vllm in a separate step

Author: dtrifiro

.github/workflows/tests.yaml

@@ -98,6 +98,11 @@ jobs:
           path: /home/runner/.cache/ccache
           key: ${{ runner.os }}
 
+      - name: build vllm
+        run: nox --envdir ~/.nox --reuse-venv=yes -v -s build_vllm-${{ matrix.pyv }}
+        env:
+          VLLM_VERSION_OVERRIDE: ${{ matrix.vllm_version }}
+
       - name: Run tests
         run: nox --envdir ~/.nox --reuse-venv=yes -v -s tests-${{ matrix.pyv }} -- --cov-report=xml
         env:

noxfile.py

@@ -16,6 +16,12 @@
 ]
 
 
+@nox.session(python=versions)
+def build_vllm(session: nox.Session) -> None:
+    if vllm_version := os.getenv("VLLM_VERSION_OVERRIDE"):
+        session.install(vllm_version)
+
+
 @nox.session(python=versions)
 def tests(session: nox.Session) -> None:
     if vllm_version := os.getenv("VLLM_VERSION_OVERRIDE"):