tests: SAVE_CONFIG error cases

Signed-off-by: Jouni Malinen <j@w1.fi>

tests/hwsim/test_wpas_config.py

@@ -113,5 +113,20 @@ def test_wpas_config_file(dev):
             logger.debug(data2)
             raise Exception("Unexpected configuration change")
 
+        wpas.request("SET update_config 0")
+        if "OK" in wpas.request("SAVE_CONFIG"):
+            raise Exception("SAVE_CONFIG succeeded unexpectedly")
+        if "OK" in wpas.global_request("SAVE_CONFIG"):
+            raise Exception("SAVE_CONFIG (global) succeeded unexpectedly")
+
+        # symlink config file to itself to break writing
+        subprocess.call(['rm', config])
+        subprocess.call(['ln', '-s', config, config])
+        wpas.request("SET update_config 1")
+        if "OK" in wpas.request("SAVE_CONFIG"):
+            raise Exception("SAVE_CONFIG succeeded unexpectedly")
+        if "OK" in wpas.global_request("SAVE_CONFIG"):
+            raise Exception("SAVE_CONFIG (global) succeeded unexpectedly")
+
     finally:
         subprocess.call(['sudo', 'rm', config])