Try CI with mambaforge on Linux+PyPy 3.7, macos, windows

.github/condarc.yml

@@ -0,0 +1,2 @@
+pkgs_dirs:
+    - ~/conda_pkgs_dir

.github/workflows/tests.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', 'pypy-3.7']
+        python-version: ['3.7', '3.8', '3.9', '3.10']
 
     steps:
     - name: Checkout
@@ -55,3 +55,54 @@ jobs:
         coveralls --service=github
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  test-more:
+    name: test (${{ matrix.os }}, ${{ matrix.miniforge-variant }})
+    runs-on: ${{ matrix.os }}-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu", "macos", "windows"]
+        include:
+          - os: ubuntu
+            condarc-file: .github/condarc.yml
+            environment-file: environment.yml
+            miniforge-variant: Mambaforge-pypy3
+          - os: macos
+            condarc-file: .github/condarc.yml
+            environment-file: environment.yml
+            miniforge-variant: Mambaforge
+          - os: windows
+            condarc-file: .github/condarc.yml
+            environment-file: environment.yml
+            miniforge-variant: Mambaforge
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Cache conda
+      uses: actions/cache@v2
+      env:
+        # Increase this value to reset cache if environment.yml has not changed
+        CACHE_NUMBER: 0
+      with:
+        path: ~/conda_pkgs_dir
+        key:
+          ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}-${{ hashFiles('environment.yml') }}
+
+    - uses: conda-incubator/setup-miniconda@v2
+      with:
+        condarc-file: ${{ matrix.condarc-file }}
+        environment-file: ${{ matrix.environment-file }}
+        miniforge-variant: ${{ matrix.miniforge-variant }}
+        use-mamba: true
+
+    - name: Verify Python environment
+      run: |
+        mamba list
+
+    - name: Install dependencies
+      run: |
+        pip install -e .[tests]
+
+    - name: Run tests
+      run: pytest -s -v -n 4

environment.yml

@@ -0,0 +1,6 @@
+channels:
+  - conda-forge
+
+dependencies:
+  - xarray
+  - pydantic