fix: test command in main.yml and bump github action versions

.github/workflows/main.yml

@@ -10,20 +10,21 @@ jobs:
       matrix:
         python-version: [ "3.9", "3.10", "3.11" ]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install apt dependencies
         run: |
           sudo apt-get update
           sudo apt-get install openmpi-bin libopenmpi-dev
+
       - name: Cache pip
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pip
-          key: ${{ runner.os }}-pip-${{ hashFiles('requirements.txt') }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('pyproject.toml') }}
           restore-keys: |
             ${{ runner.os }}-pip-
             ${{ runner.os }}-
@@ -34,5 +35,5 @@ jobs:
       - name: Run tests & coverage
         run: |
           coverage run -p -m unittest discover -v -s ./tests
-          mpiexec -n 2 coverage run -p -m unittest -v -s ./tests
+          mpiexec -n 2 coverage run -p -m unittest discover -v -s ./tests
           bash <(curl -s https://codecov.io/bash)