test(integration): add unittest-based repository layout contract test

- Add integration test using unittest to verify canonical repository paths
- Assert pkgmgr repository satisfies template layout (packaging, changelog, metadata)
- Use real filesystem without mocks or pytest dependencies

https://chatgpt.com/share/693eaa75-98f0-800f-adca-439555f84154

tests/integration/test_repository_paths_exist.py

@@ -1,11 +1,9 @@
-# tests/integration/test_repository_paths_exist.py
 from __future__ import annotations
 
 import os
+import unittest
 from pathlib import Path
 
-import pytest
-
 from pkgmgr.core.repository.paths import resolve_repo_paths
 
 
@@ -13,7 +11,7 @@ def _find_repo_root() -> Path:
     """
     Locate the pkgmgr repository root from the test location.
 
-    This assumes the standard layout:
+    Assumes:
       repo_root/
         src/pkgmgr/...
         tests/integration/...
@@ -25,40 +23,43 @@ def _find_repo_root() -> Path:
     raise RuntimeError("Could not determine repository root for pkgmgr integration test")
 
 
-def test_pkgmgr_repository_paths_exist() -> None:
+class TestRepositoryPathsExist(unittest.TestCase):
     """
-    Integration test: verify that the pkgmgr repository provides all
-    canonical files defined by RepoPaths.
-
-    pkgmgr acts as the TEMPLATE repository for all other packages.
-    Therefore, every path resolved here is expected to exist.
+    Integration test: pkgmgr is the TEMPLATE repository.
+    All canonical paths resolved for pkgmgr must exist.
     """
-    repo_root = _find_repo_root()
-    paths = resolve_repo_paths(str(repo_root))
 
-    missing: list[str] = []
+    def test_pkgmgr_repository_paths_exist(self) -> None:
+        repo_root = _find_repo_root()
+        paths = resolve_repo_paths(str(repo_root))
 
-    def _require(path: str | None, description: str) -> None:
-        if not path:
-            missing.append(f"{description}: <not resolved>")
-            return
-        if not os.path.isfile(path):
-            missing.append(f"{description}: {path} (missing)")
+        missing: list[str] = []
 
-    # Core metadata (must always exist)
-    _require(paths.pyproject_toml, "pyproject.toml")
-    _require(paths.flake_nix, "flake.nix")
+        def require(path: str | None, description: str) -> None:
+            if not path:
+                missing.append(f"{description}: <not resolved>")
+                return
+            if not os.path.isfile(path):
+                missing.append(f"{description}: {path} (missing)")
 
-    # Human-facing changelog (pkgmgr must provide one)
-    _require(paths.changelog_md, "CHANGELOG.md")
+        # Core metadata
+        require(paths.pyproject_toml, "pyproject.toml")
+        require(paths.flake_nix, "flake.nix")
 
-    # Packaging files (pkgmgr is the reference implementation)
-    _require(paths.arch_pkgbuild, "Arch PKGBUILD")
-    _require(paths.debian_changelog, "Debian changelog")
-    _require(paths.rpm_spec, "RPM spec file")
+        # Human changelog
+        require(paths.changelog_md, "CHANGELOG.md")
 
-    if missing:
-        pytest.fail(
-            "pkgmgr repository does not satisfy the canonical repository layout:\n"
-            + "\n".join(f"  - {item}" for item in missing)
-        )
+        # Packaging files (pkgmgr defines the template)
+        require(paths.arch_pkgbuild, "Arch PKGBUILD")
+        require(paths.debian_changelog, "Debian changelog")
+        require(paths.rpm_spec, "RPM spec file")
+
+        if missing:
+            self.fail(
+                "pkgmgr repository does not satisfy the canonical repository layout:\n"
+                + "\n".join(f"  - {item}" for item in missing)
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()