add benchmark to CI

.github/workflows/CI.yml

@@ -477,3 +477,60 @@ jobs:
         run: |
           source ~/test_env/bin/activate
           pytest elephant --doctest-modules --ignore=elephant/test/
+
+  # install dependencies and elephant with pip and run tests with pytest
+  benchmark:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        # python versions for elephant: [3.8, 3.9, "3.10", 3.11]
+        python-version: [3.11]
+        # OS [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest]
+      # do not cancel all in-progress jobs if any matrix job fails
+      fail-fast: false
+
+    steps:
+      # used to reset cache every month
+      - name: Get current year-month
+        id: date
+        run: echo "date=$(date +'%Y-%m')" >> $GITHUB_OUTPUT
+
+      - uses: actions/checkout@v3
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+          cache-dependency-path: '**/requirements.txt'
+
+      - name: Cache test_env
+        uses: actions/cache@v3
+        with:
+          path: /home/runner/.benchmarks
+          # Look to see if there is a cache hit for the corresponding requirements files
+          # cache will be reset on changes to any requirements or every month
+          key: ${{ runner.os }}-venv-${{ hashFiles('**/requirements.txt') }}-${{ hashFiles('**/requirements-tests.txt') }}
+            -${{ hashFiles('**/requirements-extras.txt') }}-${{ hashFiles('**/CI.yml') }}-${{ hashFiles('setup.py') }}
+            -${{ steps.date.outputs.date }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install coveralls
+          pip install -r requirements/requirements-tests.txt
+          pip install -r requirements/requirements.txt
+          pip install -r requirements/requirements-extras.txt
+          pip install -e .
+
+      - name: List packages
+        run: |
+          pip list
+          python --version
+
+      - name: Benchmark with pytest-benchmark
+        run: |
+          pytest --benchmark-only --benchmark-compare --benchmark-autosave
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}