Add test to check extension_modules value alignment

tests/pytests/unit/cli/test_salt_call.py

@@ -0,0 +1,32 @@
+import os
+
+from salt.cli.call import SaltCall
+from tests.support.mock import MagicMock, patch
+
+
+def test_passing_cachedir_to_extension_modules(temp_salt_minion):
+    """
+    Test passing `cachedir` CLI parameter to `extension_modules` opts
+    """
+    test_cache_dir = os.path.join(temp_salt_minion.config["root_dir"], "new_cache_tmp")
+    with patch(
+        "sys.argv",
+        [
+            "salt-call",
+            "--local",
+            "--config-dir",
+            temp_salt_minion.config["root_dir"],
+            "--cachedir",
+            test_cache_dir,
+            "test.true",
+        ],
+    ), patch("salt.utils.verify.verify_files", MagicMock()), patch(
+        "salt._logging.impl.setup_logfile_handler", MagicMock()
+    ):
+        salt_call = SaltCall()
+        with patch("salt.cli.caller.Caller.factory", MagicMock()) as caller_mock:
+            salt_call.run()
+            assert salt_call.config["cachedir"] == test_cache_dir
+            assert salt_call.config["extension_modules"] == os.path.join(
+                test_cache_dir, "extmods"
+            )