Add test for match_hostname.

test/test_connection.py

@@ -47,6 +47,36 @@ def test_match_hostname_mismatch(self):
             )
             assert e._peer_cert == cert
 
+    def test_match_hostname_no_dns(self):
+        cert = {"subjectAltName": [("DNS", "")]}
+        asserted_hostname = "bar"
+        try:
+            with mock.patch("urllib3.connection.log.warning") as mock_log:
+                _match_hostname(cert, asserted_hostname)
+        except CertificateError as e:
+            assert "hostname 'bar' doesn't match ''" in str(e)
+            mock_log.assert_called_once_with(
+                "Certificate did not match expected hostname: %s. Certificate: %s",
+                "bar",
+                {"subjectAltName": [("DNS", "")]},
+            )
+            assert e._peer_cert == cert
+
+    def test_match_hostname_startwith_wildcard(self):
+        cert = {"subjectAltName": [("DNS", "*foo")]}
+        asserted_hostname = "barfoo"
+        _match_hostname(cert, asserted_hostname)
+
+    def test_match_hostname_dnsname(self):
+        cert = {"subjectAltName": [("DNS", "xn--p1b6ci4b4b3a*.xn--11b5bs8d")]}
+        asserted_hostname = "xn--p1b6ci4b4b3a*.xn--11b5bs8d"
+        _match_hostname(cert, asserted_hostname)
+
+    def test_match_hostname_include_wildcard(self):
+        cert = {"subjectAltName": [("DNS", "foo*")]}
+        asserted_hostname = "foobar"
+        _match_hostname(cert, asserted_hostname)
+
     def test_match_hostname_ignore_common_name(self):
         cert = {"subject": [("commonName", "foo")]}
         asserted_hostname = "foo"