Capture the target expectation of normalized names.

Author: jaraco

importlib_metadata/__init__.py

@@ -473,7 +473,7 @@ def search(self, name):
         for child in self.children():
             n_low = child.lower()
             if (n_low in name.exact_matches
-                    or n_low.replace('.', '_').startswith(name.prefix)
+                    or n_low.startswith(name.prefix)
                     and n_low.endswith(name.suffixes)
                     # legacy case:
                     or self.is_egg(name) and n_low == 'egg-info'):
@@ -494,12 +494,19 @@ def __init__(self, name):
         self.name = name
         if name is None:
             return
-        self.normalized = name.lower().replace('-', '_')
+        self.normalized = self.normalize(name)
         self.prefix = self.normalized + '-'
         self.exact_matches = [
             self.normalized + suffix for suffix in self.suffixes]
         self.versionless_egg_name = self.normalized + '.egg'
 
+    @staticmethod
+    def normalize(name):
+        """
+        PEP 503 normalization plus dashes as underscores.
+        """
+        return re.sub(r"[-_.]+", "-", name).lower().replace('-', '_')
+
 
 @install
 class MetadataPathFinder(NullFinder, DistributionFinder):

tests/fixtures.py

@@ -106,7 +106,7 @@ def setUp(self):
 
 class DistInfoPkgWithDot(OnSysPath, SiteDir):
     files = {
-        "pkg.dot-1.0.0.dist-info": {
+        "pkg_dot-1.0.0.dist-info": {
             "METADATA": """
                 Name: pkg.dot
                 Version: 1.0.0

tests/test_api.py

@@ -42,8 +42,11 @@ def test_for_name_does_not_exist(self):
         with self.assertRaises(PackageNotFoundError):
             distribution('does-not-exist')
 
-    def test_for_name_containing_dot(self):
-        assert distribution('pkg-dot').metadata['Name'] == 'pkg.dot'
+    def test_name_normalization(self):
+        names = 'pkg.dot', 'pkg_dot', 'pkg-dot', 'pkg..dot', 'Pkg.Dot'
+        for name in names:
+            with self.subTest(name):
+                assert distribution(name).metadata['Name'] == 'pkg.dot'
 
     def test_for_top_level(self):
         self.assertEqual(