perf/tests: use more appropriate data type for package filter policy packages and add tests

src/poetry/config/config.py

@@ -83,14 +83,14 @@ def build_config_setting_normalizer(val: str) -> Mapping[str, str | Sequence[str
 @dataclasses.dataclass
 class PackageFilterPolicy:
     policy: dataclasses.InitVar[str | list[str] | None]
-    packages: list[str] = dataclasses.field(init=False)
+    packages: frozenset[str] = dataclasses.field(init=False)
 
     def __post_init__(self, policy: str | list[str] | None) -> None:
         if not policy:
             policy = []
         elif isinstance(policy, str):
             policy = self.normalize(policy)
-        self.packages = policy
+        self.packages = frozenset(policy)
 
     def allows(self, package_name: str) -> bool:
         if ":all:" in self.packages:

tests/config/test_config.py

@@ -13,6 +13,7 @@
 from deepdiff.diff import DeepDiff
 
 from poetry.config.config import Config
+from poetry.config.config import PackageFilterPolicy
 from poetry.config.config import boolean_normalizer
 from poetry.config.config import int_normalizer
 from poetry.config.config import str_list_normalizer
@@ -50,6 +51,16 @@ def test_str_list_normalizer(value: str, expected: list[str]) -> None:
     assert str_list_normalizer(value) == expected
 
 
+def test_package_filter_policy_normalizes_and_matches_packages() -> None:
+    policy = PackageFilterPolicy("PyTest,black")
+
+    assert policy.packages == frozenset({"black", "pytest"})
+    assert policy.allows("Poetry")
+    assert not policy.allows("PyTest")
+    assert policy.has_exact_package("PyTest")
+    assert not policy.has_exact_package("Poetry")
+
+
 @pytest.mark.parametrize(
     ("name", "value"),
     [