PYTHON-3110 Remove use of example.com in CSFLE tests (mongodb#848)

(cherry picked from commit 561ee7c)

Author: ShaneHarvey

test/test_encryption.py

@@ -1174,16 +1174,17 @@ def setUp(self):
             kms_tls_options=KMS_TLS_OPTS)
 
         kms_providers_invalid = copy.deepcopy(kms_providers)
-        kms_providers_invalid['azure']['identityPlatformEndpoint'] = 'example.com:443'
-        kms_providers_invalid['gcp']['endpoint'] = 'example.com:443'
+        kms_providers_invalid['azure']['identityPlatformEndpoint'] = 'doesnotexist.invalid:443'
+        kms_providers_invalid['gcp']['endpoint'] = 'doesnotexist.invalid:443'
         kms_providers_invalid['kmip']['endpoint'] = 'doesnotexist.local:5698'
         self.client_encryption_invalid = ClientEncryption(
             kms_providers=kms_providers_invalid,
             key_vault_namespace='keyvault.datakeys',
             key_vault_client=client_context.client,
             codec_options=OPTS,
             kms_tls_options=KMS_TLS_OPTS)
-        self._kmip_host_error = ''
+        self._kmip_host_error = None
+        self._invalid_host_error = None
 
     def tearDown(self):
         self.client_encryption.close()
@@ -1264,9 +1265,9 @@ def test_06_aws_endpoint_invalid_host(self):
             "region": "us-east-1",
             "key": ("arn:aws:kms:us-east-1:579766882180:key/"
                     "89fcc2c4-08b0-4bd9-9f25-e30687b580d0"),
-            "endpoint": "example.com"
+            "endpoint": "doesnotexist.invalid"
         }
-        with self.assertRaisesRegex(EncryptionError, 'parse error'):
+        with self.assertRaisesRegex(EncryptionError, self.invalid_host_error):
             self.client_encryption.create_data_key(
                 'aws', master_key=master_key)
 
@@ -1278,8 +1279,8 @@ def test_07_azure(self):
         self.run_test_expected_success('azure', master_key)
 
         # The full error should be something like:
-        # "Invalid JSON in KMS response. HTTP status=404. Error: Got parse error at '<', position 0: 'SPECIAL_EXPECTED'"
-        with self.assertRaisesRegex(EncryptionError, 'parse error'):
+        # "[Errno 8] nodename nor servname provided, or not known"
+        with self.assertRaisesRegex(EncryptionError, self.invalid_host_error):
             self.client_encryption_invalid.create_data_key(
                 'azure', master_key=master_key)
 
@@ -1295,8 +1296,8 @@ def test_08_gcp_valid_endpoint(self):
         self.run_test_expected_success('gcp', master_key)
 
         # The full error should be something like:
-        # "Invalid JSON in KMS response. HTTP status=404. Error: Got parse error at '<', position 0: 'SPECIAL_EXPECTED'"
-        with self.assertRaisesRegex(EncryptionError, 'parse error'):
+        # "[Errno 8] nodename nor servname provided, or not known"
+        with self.assertRaisesRegex(EncryptionError, self.invalid_host_error):
             self.client_encryption_invalid.create_data_key(
                 'gcp', master_key=master_key)
 
@@ -1308,30 +1309,38 @@ def test_09_gcp_invalid_endpoint(self):
             "location": "global",
             "keyRing": "key-ring-csfle",
             "keyName": "key-name-csfle",
-            "endpoint": "example.com:443"}
+            "endpoint": "doesnotexist.invalid:443"}
 
         # The full error should be something like:
         # "Invalid KMS response, no access_token returned. HTTP status=200"
         with self.assertRaisesRegex(EncryptionError, "Invalid KMS response"):
             self.client_encryption.create_data_key(
                 'gcp', master_key=master_key)
 
-    def kmip_host_error(self):
-        if self._kmip_host_error:
-            return self._kmip_host_error
+    def dns_error(self, host, port):
         # The full error should be something like:
         # "[Errno 8] nodename nor servname provided, or not known"
-        try:
-            socket.getaddrinfo('doesnotexist.local', 5698, socket.AF_INET,
-                               socket.SOCK_STREAM)
-        except Exception as exc:
-            self._kmip_host_error = re.escape(str(exc))
-            return self._kmip_host_error
+        with self.assertRaises(Exception) as ctx:
+            socket.getaddrinfo(host, port, socket.AF_INET, socket.SOCK_STREAM)
+        return re.escape(str(ctx.exception))
+
+    @property
+    def invalid_host_error(self):
+        if self._invalid_host_error is None:
+            self._invalid_host_error = self.dns_error(
+                'doesnotexist.invalid', 443)
+        return self._invalid_host_error
+
+    @property
+    def kmip_host_error(self):
+        if self._kmip_host_error is None:
+            self._kmip_host_error = self.dns_error('doesnotexist.local', 5698)
+        return self._kmip_host_error
 
     def test_10_kmip_invalid_endpoint(self):
         key = {'keyId': '1'}
         self.run_test_expected_success('kmip', key)
-        with self.assertRaisesRegex(EncryptionError, self.kmip_host_error()):
+        with self.assertRaisesRegex(EncryptionError, self.kmip_host_error):
             self.client_encryption_invalid.create_data_key('kmip', key)
 
     def test_11_kmip_master_key_endpoint(self):
@@ -1348,7 +1357,7 @@ def test_11_kmip_master_key_endpoint(self):
 
     def test_12_kmip_master_key_invalid_endpoint(self):
         key = {'keyId': '1', 'endpoint': 'doesnotexist.local:5698'}
-        with self.assertRaisesRegex(EncryptionError, self.kmip_host_error()):
+        with self.assertRaisesRegex(EncryptionError, self.kmip_host_error):
             self.client_encryption.create_data_key('kmip', key)