Enable Cython tests for cuda.bindings (#323)

* enable Cython tests for cuda.bindings

* build Cython test modules

* Update gh-build-and-test.yml

* Install system gcc

* No sudo

* also set CUDA_HOME

* Try to find Python include

* nit: add a skip condition and comments

* simplify

.github/actions/fetch_ctk/action.yml

@@ -146,5 +146,6 @@ runs:
       run: |
         CUDA_PATH=$(realpath "./cuda_toolkit")
         echo "CUDA_PATH=${CUDA_PATH}" >> $GITHUB_ENV
+        echo "CUDA_HOME=${CUDA_PATH}" >> $GITHUB_ENV
         echo "${CUDA_PATH}/bin" >> $GITHUB_PATH
         echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH:-}:${CUDA_PATH}/lib" >> $GITHUB_ENV

.github/workflows/build-and-test.yml

@@ -234,6 +234,9 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+        env:
+          # we use self-hosted runners on which setup-python behaves weirdly...
+          AGENT_TOOLSDIRECTORY: "/opt/hostedtoolcache"
 
       - name: Set up mini CTK
         uses: ./.github/actions/fetch_ctk
@@ -255,6 +258,13 @@ jobs:
           pushd ./cuda_bindings
           pip install -r requirements.txt
           pytest -rxXs tests/
-          # TODO: enable cython tests
-          #pytest tests/cython
+          if [[ "${{ matrix.host-platform }}" == linux* ]]; then
+            # cython tests require gcc
+            apt install -y build-essential
+            bash tests/cython/build_tests.sh
+          elif [[ "${{ matrix.host-platform }}" == win* ]]; then
+            # TODO: enable this once win-64 runners are up 
+            exit 1
+          fi  
+          pytest -rxXs tests/cython
           popd