test: refactor test_client_facades

Explicitly test assumptions about facade name and version numbering, and
then build the required data structure more directly in a single pass +
sorting.

Author: james-garner-canonical

tests/validate/test_facades.py

@@ -4,7 +4,7 @@
 import importlib
 import re
 from pathlib import Path
-from typing import Dict, List, Set, Tuple, TypedDict, cast
+from typing import Dict, List, TypedDict, cast
 
 import pytest
 
@@ -23,60 +23,52 @@ def project_root(pytestconfig: pytest.Config) -> Path:
     return pytestconfig.rootpath
 
 
-def test_client_facades(project_root: Path) -> None:
+def test_facade_version_matches_filename(project_root: Path) -> None:
+    ignore_names = dir(_definitions)
+    for file in (project_root / 'juju' / 'client').glob('_client[0-9]*.py'):
+        match = re.search('_client([0-9]+).py', file.name)
+        assert match
+        version = int(match.group(1))
+        module = importlib.import_module(f'juju.client.{file.stem}')
+        for cls_name in dir(module):
+            if cls_name.startswith('_') or cls_name in ignore_names:
+                continue
+            assert getattr(module, cls_name).version == version
+
+
+def test_class_name_matches_facade_name(project_root: Path) -> None:
+    ignore_names = dir(_definitions)
+    for file in (project_root / 'juju' / 'client').glob('_client[0-9]*.py'):
+        module = importlib.import_module(f'juju.client.{file.stem}')
+        for cls_name in dir(module):
+            if cls_name.startswith('_') or cls_name in ignore_names:
+                continue
+            assert getattr(module, cls_name).name == cls_name.removesuffix('Facade')
+
+
+def test_client_facades_matches_generated_code(project_root: Path) -> None:
     client_facades = cast(ClientFacades, connection.client_facades)
-    good_facades = make_client_facades_from_generated_code(project_root)
+    expected_facades = make_client_facades_from_generated_code(project_root)
     assert {
         k: v['versions'] for k, v in client_facades.items()
     } == {
-        k: v['versions'] for k, v in good_facades.items()
+        k: v['versions'] for k, v in expected_facades.items()
     }
 
 
 def make_client_facades_from_generated_code(project_root: Path) -> ClientFacades:
     """Return a client_facades dictionary from generated code under project_root.
     """
-    files_by_version: List[Tuple[int, Path]] = []
-    # [(facade_version, Path), ...]
+    ignore_names = dir(_definitions)
+    excluded_facades = connection.excluded_facades
+    facades: Dict[str, List[int]] = {}
     for file in (project_root / 'juju' / 'client').glob('_client[0-9]*.py'):
-        files_by_version.append((_version_from_filename(file), file))
-    files_by_version.sort()
-
-    # _clientN.py files import * from _definitions
-    # so we will ignore any names from there
-    ignore = dir(_definitions)
-
-    facades_by_version: Dict[int, Set[str]] = {}
-    # {facade_version: {facade_name, ...}, ...}
-    for version, file in files_by_version:
         module = importlib.import_module(f'juju.client.{file.stem}')
-        facades = {
-            name.removesuffix("Facade")
-            for name in dir(module)
-            if not (name.startswith('_') or name in ignore)
-        }
-        facades_by_version[version] = facades
-
-    # client_facades in connection.py is sorted
-    # so we sort facade names before constructing it
-    first, *rest = facades_by_version.values()
-    sorted_facade_names: list[str] = sorted(first.union(*rest))
-
-    excluded_facades = connection.excluded_facades
-    client_facades: ClientFacades = {}
-    # {facade_name: {'versions': [1, 2, 3, ...]}, ...}
-    for name in sorted_facade_names:
-        versions: List[int] = []
-        for version, facades in facades_by_version.items():
-            if version in excluded_facades.get(name, []):
+        for cls_name in dir(module):
+            if cls_name.startswith('_') or cls_name in ignore_names:
                 continue
-            if name in facades:
-                versions.append(version)
-        client_facades[name] = {'versions': versions}
-    return client_facades
-
-
-def _version_from_filename(path: Path) -> int:
-    match = re.search('_client([0-9]+).py', path.name)
-    assert match
-    return int(match.group(1))
+            cls = getattr(module, cls_name)
+            if cls.version in excluded_facades.get(cls.name, []):
+                continue
+            facades.setdefault(cls.name, []).append(cls.version)
+    return {name: {'versions': sorted(facades[name])} for name in sorted(facades)}