chore: single file & 3.6 import

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

setup.cfg

@@ -87,9 +87,9 @@ validate_pyproject.tool_schema =
     setuptools = validate_pyproject.api:load_builtin_plugin
     distutils = validate_pyproject.api:load_builtin_plugin
 repo_review.checks =
-    validate_pyproject = validate_pyproject.repo_review.checks:repo_review_checks
+    validate_pyproject = validate_pyproject.repo_review:repo_review_checks
 repo_review.families =
-    validate_pyproject = validate_pyproject.repo_review.families:repo_review_families
+    validate_pyproject = validate_pyproject.repo_review:repo_review_families
 
 [tool:pytest]
 # Specify command line options as you would do when invoking pytest directly.

src/validate_pyproject/repo_review.py

@@ -0,0 +1,36 @@
+from typing import Any, Dict
+
+import fastjsonschema
+
+from .. import api, plugins
+
+__all__ = ["VPP001", "repo_review_checks", "repo_review_families"]
+
+
+class VPP001:
+    """Validate pyproject.toml"""
+
+    family = "validate-pyproject"
+
+    @staticmethod
+    def check(pyproject: Dict[str, Any]) -> str:
+        validator = api.Validator()
+        try:
+            validator(pyproject)
+            return ""
+        except fastjsonschema.JsonSchemaValueException as e:
+            return f"Invalid pyproject.toml! Error: {e}"
+
+
+def repo_review_checks() -> Dict[str, VPP001]:
+    return {"VPP001": VPP001()}
+
+
+def repo_review_families(pyproject: Dict[str, Any]) -> Dict[str, Dict[str, str]]:
+    has_distutils = "distutils" in pyproject.get("tool", {})
+    plugin_names = (ep.name for ep in plugins.iterate_entry_points())
+    plugin_list = (
+        f"`[tool.{n}]`" for n in plugin_names if n != "distutils" or has_distutils
+    )
+    descr = f"Checks `[build-system]`, `[project]`, {', '.join(plugin_list)}"
+    return {"validate-pyproject": {"name": "Validate-PyProject", "description": descr}}