sacch: Add a testcase for channel release with no LAPDm UA/UM

Test that the channel is released even when a phone does not
release the main signalling link. This is simulated by ignoring
the GSM48 RR channel release and waiting for two SAPI release
requests.

sacch_timeout/README

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+Test that not responding release message still results in a channel release.

sacch_timeout/SACCHTimeout.st

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+"
+ (C) 2012 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PackageLoader fileInPackage: #FakeBTS.
+
+FakeBTS.OpenBSCTest subclass: SACCHTimeout [
+    <import: OsmoGSM>
+
+    SACCHTimeout class >> cpDataRpData [
+        ^ #(
+            16r09 16r01 16r35 16r01 16r2A 16r07 16r91 16r44
+            16r77 16r58 16r10 16r06 16r50 16r00 16r2B 16r04
+            16r04 16r81 16r32 16r24 16r00 16r00 16r80 16r21
+            16r03 16r41 16r24 16r32 16r40 16r1F 16r41 16r26
+            16r03 16r94 16r7D 16r56 16rA5 16r20 16r28 16rF2
+            16rE9 16r2C 16r82 16r82 16rD2 16r22 16r48 16r58
+            16r64 16r3E 16r9D 16r47 16r10 16rF5 16r09 16rAA
+            16r4E 16r01) asByteArray.
+    ]
+
+    startTest [
+        "1. Connect to the BTS"
+        self createAndConnectBTS: '1801/0/0'.
+
+        self
+            testCPTimeoutSacchTimeout.
+    ]
+
+
+    testCPTimeoutSacchTimeout [
+        | lchan cm tmsi wait |
+
+        tmsi := self allocateTmsi: '901010000001111'.
+
+        "2. Get a LCHAN"
+        lchan := self requireAnyChannel.
+
+	"Prepare the waiting"
+	wait := Semaphore new.
+        lchan onReleaseReqCB: [:sapi |
+            Transcript nextPutAll: 'Releasing'; nl. wait signal].
+
+        "3. Send a CM Service Request "
+        cm := GSM48CMServiceReq new.
+        cm mi tmsi: tmsi.
+        lchan sendGSM: cm toMessage.
+
+	"4. CP-DATA/RP-DATA PDU"
+	lchan sendGSM: self class cpDataRpData sapi: 3.
+
+        "Wait for the channel to be released.."
+	wait wait; wait.
+        Transcript nextPutAll: 'Channel was released.'; nl.
+    ]
+]
+
+Eval [
+    | test |
+
+    test := SACCHTimeout new
+                startTest;
+                stopBts;
+                yourself.
+]