nitb/ctrl: Add ctrl command to set the TRX max_power_reduction

In case the BTS is connected the new attribute should be set
through OML. This is left as a todo item.

Addresses: SYS#267
diff --git a/openbsc/tests/ctrl_test_runner.py b/openbsc/tests/ctrl_test_runner.py
index 22f378d..afcd42c 100644
--- a/openbsc/tests/ctrl_test_runner.py
+++ b/openbsc/tests/ctrl_test_runner.py
@@ -176,6 +176,26 @@
         self.assertEquals(r['mtype'], 'ERROR')
         self.assertEquals(r['error'], 'Error while resolving object')
 
+    def testTrxPowerRed(self):
+        r = self.do_get('bts.0.trx.0.max-power-reduction')
+        self.assertEquals(r['mtype'], 'GET_REPLY')
+        self.assertEquals(r['var'], 'bts.0.trx.0.max-power-reduction')
+        self.assertEquals(r['value'], '20')
+
+        r = self.do_set('bts.0.trx.0.max-power-reduction', '22')
+        self.assertEquals(r['mtype'], 'SET_REPLY')
+        self.assertEquals(r['var'], 'bts.0.trx.0.max-power-reduction')
+        self.assertEquals(r['value'], '22')
+        
+        r = self.do_get('bts.0.trx.0.max-power-reduction')
+        self.assertEquals(r['mtype'], 'GET_REPLY')
+        self.assertEquals(r['var'], 'bts.0.trx.0.max-power-reduction')
+        self.assertEquals(r['value'], '22')
+        
+        r = self.do_set('bts.0.trx.0.max-power-reduction', '1')
+        self.assertEquals(r['mtype'], 'ERROR')
+        self.assertEquals(r['error'], 'Value must be even')
+
     def testRfLock(self):
         r = self.do_get('bts.0.rf_state')
         self.assertEquals(r['mtype'], 'GET_REPLY')