fakebts: Implement forwarding the paging requests by the BSC

Code can use OpenBSCTest>>#bts to access the BTS and re-act to paging
by the BSC.

fakebts/BTS.st

@@ -155,8 +155,16 @@ RSLReleaseRequest extend [
     ]
 ]
 
+RSLPagingCommand extend [
+    trxDispatchOn: aTrx [
+	<category: '*-BTS-Core'>
+	aTrx mainBts paging: self msIdenity.
+    ]
+]
+
 Object subclass: BTS [
-    | site_mgr oml rsl oml_queue oml_init connected oml_up ras ras_mutex bts_id |
+    | site_mgr oml rsl oml_queue oml_init connected oml_up ras ras_mutex
+      bts_id on_paging |
     <category: 'BTS-Core'>
     <comment: 'A fake BTS to test the state machine and inject
     RSL messages to test a network without RF.'>
@@ -373,4 +381,12 @@ Object subclass: BTS [
         ras_mutex critical: [ras identityRemove: entry ifAbsent: []].
         ^ out_chan
     ]
+
+    paging: aPaging [
+	on_paging ifNotNil: [on_paging value: aPaging]
+    ]
+
+    onPaging: aCallback [
+	on_paging := aCallback
+    ]
 ]

fakebts/OpenBSCTest.st

@@ -133,6 +133,11 @@ Object subclass: OpenBSCTest [
             waitForBTSReady.
     ]
 
+    bts [
+	<category: 'accessing'>
+	^ bts
+    ]
+
     stopBts [
         <category: 'bts'>
         bts stop.