chore: Update the testcases to check against google auth version number and skip for unsupported version number

Signed-off-by: Radhika Agrawal <agrawalradhika@google.com>

Author: agrawalradhika-cell

tests/test_discovery.py

@@ -32,6 +32,7 @@
 import json
 import os
 import pickle
+import pytest
 import re
 import sys
 import unittest
@@ -40,6 +41,7 @@
 
 import google.api_core.exceptions
 import google.auth.credentials
+from google.auth import __version__ as auth_version
 from google.auth.exceptions import MutualTLSChannelError
 import google_auth_httplib2
 import httplib2
@@ -61,6 +63,7 @@
 except ImportError:
     HAS_UNIVERSE = False
 
+from google.api_core import parse_version_to_tuple
 from googleapiclient import _helpers as util
 from googleapiclient.discovery import (DISCOVERY_URI,
                                        MEDIA_BODY_PARAMETER_DEFAULT_VALUE,
@@ -889,6 +892,11 @@ def test_mtls_with_provided_client_cert(
             ("always", "", CONFIG_DATA_WITHOUT_WORKLOAD, MTLS_ENDPOINT),
         ]
     )
+    @pytest.mark.skipif(
+        parse_version_to_tuple(auth_version) < (2,43,0),
+        reason="automatic mtls enablement when supported certs present only"
+        "enabled in google-auth<=2.43.0"
+    )
     def test_mtls_with_provided_client_cert_unset_environment_variable(
         self, use_mtls_env, use_client_cert, config_data, base_url
     ):
@@ -1016,6 +1024,11 @@ def test_mtls_with_default_client_cert(
     @mock.patch(
         "google.auth.transport.mtls.default_client_encrypted_cert_source", autospec=True
     )
+    @pytest.mark.skipif(
+        parse_version_to_tuple(auth_version) < (2,43,0),
+        reason="automatic mtls enablement when supported certs present only"
+        "enabled in google-auth<=2.43.0"
+    )
     def test_mtls_with_default_client_cert_with_unset_environment_variable(
         self,
         use_mtls_env,