Try adding a simple CI script for GithubActions.

Also, let's require Cython when building (for now).  This is probably safest for now (i.e., less error prone).
Someday, somebody may want to be able to install from source w/o Cython using only .c files.

Author: eriknw

.github/workflows/test.yml

@@ -0,0 +1,40 @@
+name: python-suitesparse-graphblas
+
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        python-version: [3.7, 3.8, 3.9]
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Conda
+      uses: conda-incubator/setup-miniconda@v2
+      with:
+        auto-update-conda: true
+        python-version: ${{ matrix.python-version }}
+        channels: conda-forge
+    - name: Build
+      run: |
+        conda info
+        conda list
+        conda install -c conda-forge cffi cython numpy graphblas pytest coverage black flake8  # TODO: environment.yml
+        python setup.py build_ext --inplace
+        python setup.py develop
+    - name: Test
+      env:
+        CYTHON_COVERAGE: true
+      run: |
+        coverage run --branch -m pytest
+    - name: Lint
+      run: |
+        black *py suitesparse_graphblas --check --diff
+        flake8 *py suitesparse_graphblas

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["setuptools", "wheel", "numpy>=1.15"]
+requires = ["setuptools", "wheel", "numpy>=1.15", "cython"]
 
 [tool.black]
 line-length = 100

setup.py

@@ -25,6 +25,13 @@
         define_macros.append(("CYTHON_TRACE_NOGIL", "1"))
 else:
     suffix = ".c"
+    # Make sure all required .c files are here
+    pyx_files = glob("suitesparse_graphblas/**.pyx", recursive=True)
+    c_files = glob("suitesparse_graphblas/**.c", recursive=True)
+    missing = {x[:-4] for x in pyx_files} - {x[:-2] for x in c_files}
+    if missing:
+        missing_c = sorted(x + ".c" for x in missing)
+        raise RuntimeError("Cython required when missing C files: " + ", ".join(missing_c))
 
 include_dirs = [np.get_include(), os.path.join(sys.prefix, "include")]
 ext_modules = [

suitesparse_graphblas/create_headers.py

@@ -32,7 +32,7 @@
 
 
 def sort_key(string):
-    """ e.g., sort 'INT8' before 'INT16'"""
+    """e.g., sort 'INT8' before 'INT16'"""
     return string.replace("8", "08")
 
 

suitesparse_graphblas/tests/test_package.py

@@ -1,4 +1,4 @@
-from suitesparse_graphblas import lib, ffi
+from suitesparse_graphblas import lib, ffi  # noqa
 
 
 def test_matrix_existence():