Update src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: m-chau

src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py

@@ -21448,27 +21448,31 @@ def test_aks_upgrade_upgrade_settings(self, resource_group, resource_group_locat
     @AllowLargeResponse()
     @AKSCustomResourceGroupPreparer(random_name_length=17, name_prefix='clitest', location='westus2')
     def test_aks_upgrade_with_tier_switch(self, resource_group, resource_group_location):
-        """ This test case exercises enabling LTS tier with upgrade command."""
+        """ This test case exercises switching from LTS tier with upgrade command."""
 
         # reset the count so in replay mode the random names will start with 0
         self.test_resources_count = 0
         # kwargs for string formatting
         aks_name = self.create_random_name('cliakstest', 16)
 
-        # Pick the oldest community-supported version
+        # Pick the oldest community-supported version as the upgrade target.
         non_lts_version = self._get_oldest_non_lts_version(resource_group_location)
         if non_lts_version is None:
             self.skipTest('No community-supported versions found in the location')
 
-        # Use the 2nd latest available LTS-only version
+        # Use the latest available LTS-only version as the source version.
         lts_version = self._get_latest_lts_version(resource_group_location)
         if lts_version is None:
             self.skipTest('No LTS-only versions found in the location')
 
-        # ensure non_lts_version and lts_version has less than 3 minor version difference,
-        # otherwise the upgrade will not be allowed
+        # This test performs an upgrade while switching away from the LTS support plan,
+        # so the target version must be newer than the source version.
+        if version_to_tuple(non_lts_version) <= version_to_tuple(lts_version):
+            self.skipTest('No newer community-supported version is available for upgrade from the selected LTS version')
+
+        # Ensure the upgrade path stays within the allowed minor-version window.
         if self._get_minor_version(non_lts_version) - self._get_minor_version(lts_version) > 3:
-            self.skipTest('Non-LTS version and LTS version has more than 3 minor version difference')
+            self.skipTest('Non-LTS version and LTS version have more than 3 minor versions difference')
 
         self.kwargs.update({
             'resource_group': resource_group,