Github action script replacing travis

.github/workflows/main.yaml

@@ -0,0 +1,64 @@
+# main test workflow; ported from .travis.yaml
+
+name: main
+
+on:
+  push:
+    branches: [ '*', $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+        NUMPY_VERSION: 1.15
+    defaults:
+      run:
+        shell: bash -l {0}
+    strategy:
+        matrix:
+            python-version: ['2.7', '3.7','3.10', '3.12']
+    steps:
+    - name: Checkout source code
+      uses: actions/checkout@v4
+    - name: Setup Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Cache conda
+      uses: actions/cache@v4
+      env:
+        # Increase this value to reset cache.
+        CACHE_NUMBER: 0
+      with:
+        path: ~/conda_pkgs_dir
+        key:
+          ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}
+
+    - name: Setup Conda Environment
+      uses: conda-incubator/setup-miniconda@v3
+      with:
+        miniconda-version: latest
+        activate-environment: test
+        environment-file: maintainer/conda-env.yaml
+        channels: bccp
+        show-channel-urls: true
+        use-only-tar-bz2: true
+
+    - run:
+        conda info
+
+    - name: Build
+      run: |
+        conda install --yes numpy cython mpi4py nose
+        python -m build
+    - name: Unit tests
+      run: |
+        pip install runtests
+        python ./runtests.py --mpirun="mpirun -np 4"
+        mpirun -n 1 python $PWD/scripts/pfft-roundtrip-matrix.py -v -diag -Nproc 1 1 -Nmesh 13 15 16
+        mpirun -n 2 python $PWD/scripts/pfft-roundtrip-matrix.py -v -diag -Nproc 2 1 -Nproc 1 2 -Nmesh 13 15 16
+        mpirun -n 4 python $PWD/scripts/pfft-roundtrip-matrix.py -v -diag -Nproc 2 2 -Nmesh 13 15 16
+        mpirun -n 4 python $PWD/scripts/pfft-roundtrip-matrix.py -v -diag -Nproc 2 2 -Nmesh 13 15
+        bash check_tag.sh pfft/version.py