CI: Add cupy gpu tests

Author: steppi

.github/workflows/gpu_tests.yml

@@ -0,0 +1,56 @@
+name: GPU jobs
+
+on: [ push, pull_request ]
+
+permissions:
+   contents: read  # to fetch code (actions/checkout)
+
+env:
+  CCACHE_DIR: "${{ github.workspace }}/.ccache"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  get_commit_message:
+    name: Get commit message
+    uses: ./.github/workflows/commit_message.yml
+
+  cupy_tests:
+    name: CuPy GPU
+    needs: get_commit_message
+    if: >
+      needs.get_commit_message.outputs.message == 1
+      && (github.repository == 'scipy/xsf' || github.repository == '')
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64-gpu:22.04
+    steps:
+      - name: Checkout xsf repo
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          submodules: recursive
+
+      - name: Setup compiler cache
+        uses: cirruslabs/cache@v4  #caa3ad0624c6c2acd8ba50ad452d1f44bba078bb # v4
+        with:
+          path: ${{ env.CCACHE_DIR }}
+          # Make primary key unique by using `run_id`, this ensures the cache
+          # is always saved at the end.
+          key: ${{ runner.os }}-gpu-ccache-${{ github.run_id }}
+          restore-keys: |
+            ${{ runner.os }}-gpu-ccache
+
+      - name: run nvidia-smi
+        run: nvidia-smi
+
+      - name: run nvidia-smi --query
+        run: nvidia-smi --query
+
+      - uses: prefix-dev/setup-pixi@ba3bb36eb2066252b2363392b7739741bb777659 # v0.8.1
+        with:
+          pixi-version: v0.39.2
+          manifest-path: pixi.toml
+          cache: false
+
+      - name: Run CuPy tests
+        run: pixi run test-cupy