Add ability to identify min_python version

README.md

@@ -1 +1,9 @@
 # pinfo
+
+## Detect minimum version of python
+
+```python
+from ppinfo import Project
+p = Project(".")
+print(p.min_python)  # value from your setup.cfg
+```

src/ppinfo/__init__.py

@@ -1 +1,29 @@
 """ppinfo package."""
+import configparser
+import os
+from pathlib import Path
+from typing import Union
+
+
+# pylint: disable=too-few-public-methods
+class Project:
+    """Class representing a python project."""
+
+    # 3.7 default value is used because at the time this library was
+    # written, this was the oldest still supported version of Python
+    min_python: str = "3.7"
+
+    def __init__(self, path: Union[Path, str] = Path(".")) -> None:
+        """Construct a python Project instance."""
+        if isinstance(path, str):
+            path = Path(path)
+        self.path = path
+
+        if (path / "setup.cfg").exists():
+            config = configparser.ConfigParser()
+            config.read(path / "setup.cfg")
+            if "options" in config:
+                value = config["options"].get("python_requires", None)
+                if not (value and value.startswith(">=")):
+                    raise NotImplementedError("Unable to parse python_requires")
+                self.min_python = value[2:]

test/fixtures/proj1/setup.cfg

@@ -0,0 +1 @@
+# empty setup.cfg file

test/fixtures/py310/setup.cfg

@@ -0,0 +1,2 @@
+[options]
+python_requires = >=3.10

test/test_ppinfo.py

@@ -1,7 +1,14 @@
 """Tests for ppinfo package."""
+import pytest
 
+from ppinfo import Project
 
-def test_import() -> None:
-    """Test that we can import ppinfo."""
-    # pylint: disable=unused-import,import-outside-toplevel
-    import ppinfo
+
+@pytest.mark.parametrize(
+    ("path", "expected_python"),
+    [("test/fixtures/proj1", "3.7"), ("test/fixtures/py310", "3.10")],
+)
+def test_min_version(path: str, expected_python: str) -> None:
+    """Test ability to find minimal version of python required."""
+    project = Project(path)
+    assert project.min_python == expected_python