Filter non-identifiers from module names. Fixes #442.

Author: jaraco

importlib_metadata/__init__.py

@@ -902,4 +902,9 @@ def _top_level_inferred(dist):
         f.parts[0] if len(f.parts) > 1 else inspect.getmodulename(f)
         for f in always_iterable(dist.files)
     }
-    return filter(None, opt_names)
+
+    @pass_none
+    def valid_module(name):
+        return name.isidentifier()
+
+    return filter(valid_module, opt_names)

tests/test_main.py

@@ -323,7 +323,6 @@ def test_packages_distributions_neither_toplevel_nor_files(self):
         )
         packages_distributions()
 
-    @__import__('pytest').mark.xfail(reason="442")
     def test_packages_distributions_all_module_types(self):
         """
         Test top-level modules detected on a package without 'top-level.txt'.