FIX: support pyproject in pytest job matrix (#30)

create-pytest-matrix/action.yml

@@ -35,6 +35,8 @@ runs:
     - uses: actions/setup-python@v4
       with:
         python-version: "3.8"
+    - run: pip install toml
+      shell: bash
     - id: set-matrix
       name: Create run matrix in JSON form
       run: |

create-pytest-matrix/main.py

@@ -3,10 +3,13 @@
 from __future__ import annotations
 
 import json
+import os
 from argparse import ArgumentParser
 from configparser import ConfigParser
 from typing import Sequence
 
+import toml
+
 
 def main(argv: Sequence[str] | None = None) -> int:
     parser = ArgumentParser(__doc__)
@@ -91,24 +94,57 @@ def create_job_matrix(
     return matrix
 
 
+PYPROJECT_TOML = "pyproject.toml"
+SETUP_CFG = "setup.cfg"
+CLASSIFIERS_ERROR_MSG = (
+    "This package does not have Python version classifiers, so cannot determine"
+    " intended Python versions. See https://pypi.org/classifiers."
+)
+VERSION_IDENTIFIER = "Programming Language :: Python :: 3."
+
+
 def get_supported_python_versions() -> list[str]:
+    classifiers = _get_classifiers()
+    return _determine_python_versions(classifiers)
+
+
+def _get_classifiers() -> list[str]:
+    if os.path.exists(SETUP_CFG):
+        return __get_classifiers_from_cfg(SETUP_CFG)
+    if os.path.exists(PYPROJECT_TOML):
+        return __get_classifiers_from_toml(PYPROJECT_TOML)
+    msg = f"This project does not contain a {SETUP_CFG} or {PYPROJECT_TOML}"
+    raise FileNotFoundError(msg)
+
+
+def __get_classifiers_from_cfg(path: str) -> list[str]:
     cfg = ConfigParser()
-    cfg.read("setup.cfg")
+    cfg.read(path)
     if not cfg.has_option("metadata", "classifiers"):
+        raise ValueError(CLASSIFIERS_ERROR_MSG)
+    raw = cfg.get("metadata", "classifiers")
+    return [s.strip() for s in raw.split("\n") if s.strip()]
+
+
+def __get_classifiers_from_toml(path: str) -> list[str]:
+    with open(path) as f:
+        cfg = toml.load(f)
+    classifiers = cfg.get("project", {}).get("classifiers")
+    if classifiers is None:
+        raise ValueError(CLASSIFIERS_ERROR_MSG)
+    return classifiers
+
+
+def _determine_python_versions(classifiers: list[str]) -> list[str]:
+    versions = [s for s in classifiers if s.startswith(VERSION_IDENTIFIER)]
+    if not versions:
         msg = (
-            "This package does not have Python version classifiers. See"
-            " https://pypi.org/classifiers."
+            f"{SETUP_CFG} does not have any classifiers of the form"
+            f' "{VERSION_IDENTIFIER}*"'
         )
         raise ValueError(msg)
-    raw = cfg.get("metadata", "classifiers")
-    lines = [s.strip() for s in raw.split("\n")]
-    identifier = "Programming Language :: Python :: 3."
-    classifiers = list(filter(lambda s: s.startswith(identifier), lines))
-    if not classifiers:
-        msg = f'setup.cfg does not have any classifiers of the form "{identifier}*"'
-        raise ValueError(msg)
-    prefix = identifier[:-2]
-    return [s.replace(prefix, "") for s in classifiers]
+    prefix = VERSION_IDENTIFIER[:-2]
+    return [s.replace(prefix, "") for s in versions]
 
 
 if __name__ == "__main__":