fix(services): match service aliases without case

Uppercase entries in ALIASES never resolved, because get_tag lowercased the input but not the alias. Match real tags first so a service's own tag cannot be taken by another service's alias.

tests/core/test_service_alias_case.py

@@ -0,0 +1,34 @@
+"""Service tags resolve from an alias in any case, and a real tag beats another service's alias."""
+
+from pathlib import Path
+
+import pytest
+
+
+@pytest.fixture
+def two_services(monkeypatch: pytest.MonkeyPatch) -> None:
+    """SVCA claims "SVCB" as an alias, but SVCB is a service in its own right."""
+    from unshackle.core import services
+
+    monkeypatch.setattr(services, "SERVICES", [Path("SVCA") / "__init__.py", Path("SVCB") / "__init__.py"])
+    monkeypatch.setattr(services, "ALIASES", {"SVCA": ("SVCX", "SVCB"), "SVCB": ()})
+
+
+@pytest.mark.parametrize("value", ["SVCX", "svcx", "SvCx"])
+def test_alias_resolves_in_any_case(two_services: None, value: str) -> None:
+    from unshackle.core.services import Services
+
+    assert Services.get_tag(value) == "SVCA"
+
+
+@pytest.mark.parametrize("value", ["SVCB", "svcb", "SvCb"])
+def test_real_tag_beats_another_services_alias(two_services: None, value: str) -> None:
+    from unshackle.core.services import Services
+
+    assert Services.get_tag(value) == "SVCB"
+
+
+def test_unknown_value_is_returned_unchanged(two_services: None) -> None:
+    from unshackle.core.services import Services
+
+    assert Services.get_tag("NOPE") == "NOPE"