add more coverage

tests/test_init.py

@@ -1,5 +1,7 @@
 """Test imports can happen from top-level."""
 
+import pytest
+
 import propcache
 from propcache import _helpers
 
@@ -10,3 +12,22 @@ def test_api_at_top_level():
     assert propcache.under_cached_property is not None
     assert propcache.cached_property is _helpers.cached_property
     assert propcache.under_cached_property is _helpers.under_cached_property
+
+
+def test_public_api_is_in_dir():
+    """Verify the public API is accessible in the module's dir()."""
+    assert "cached_property" in dir(propcache)
+    assert "under_cached_property" in dir(propcache)
+
+
+def test_public_api_is_in_all():
+    """Verify the public API is accessible in the module's __all__."""
+    assert "cached_property" in propcache.__all__
+    assert "under_cached_property" in propcache.__all__
+
+
+def test_importing_invalid_attr_raises():
+    """Verify importing an invalid attribute raises an AttributeError."""
+    match = r"module 'propcache' has no attribute 'invalid_attr'"
+    with pytest.raises(AttributeError, match=match):
+        propcache.invalid_attr