Change in osmo-ttcn3-hacks[master]: attempt to fix a race condition in BSC test's f_ts_dyn_mode_get

[Stefan Sperling]

Stefan Sperling has uploaded this change for review. ( 
https://gerrit.osmocom.org/11763


Change subject: attempt to fix a race condition in BSC test's f_ts_dyn_mode_get
......................................................................

attempt to fix a race condition in BSC test's f_ts_dyn_mode_get

Add two helper functions which retry a VTY command until the
result matches a regular expression or a configurable timeout
expires.

Use these functions in BSC test's f_ts_dyn_mode_get, which has
seen sporadic failures due to a race condition during channel
reconfiguration, in order to hopefully close this race.

Change-Id: I308ddb06e440c165fe1e73fe2c1fb78be2e1d510
Related: OS#3690
---
M bsc/BSC_Tests.ttcn
M library/Osmocom_VTY_Functions.ttcn
2 files changed, 24 insertions(+), 2 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/osmo-ttcn3-hacks 
refs/changes/63/11763/1

diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index e3ac707..4f5145b 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -2742,8 +2742,7 @@
 runs on test_CT return charstring {
        var charstring cmd, resp;
        cmd := "show timeslot "&int2str(bts_nr)&" "&int2str(trx_nr)&" 
"&int2str(ts_nr);
-       resp := f_vty_transceive_ret(BSCVTY, cmd);
-       return regexp(resp, "*\((*)\)*", 0);
+       return f_vty_transceive_match_regexp_retry(BSCVTY, cmd, "*\((*)\)*", 0, 
4, 1.0);
 }

 private function f_ts_dyn_mode_assert(integer bts_nr, integer trx_nr, integer 
ts_nr,
diff --git a/library/Osmocom_VTY_Functions.ttcn 
b/library/Osmocom_VTY_Functions.ttcn
index 86f58f1..4f795ad 100644
--- a/library/Osmocom_VTY_Functions.ttcn
+++ b/library/Osmocom_VTY_Functions.ttcn
@@ -1,5 +1,6 @@
 module Osmocom_VTY_Functions {
        import from TELNETasp_PortType all;
+       import from Osmocom_Types all;

        modulepar {
                charstring mp_prompt_prefix := "OpenBSC";
@@ -153,5 +154,27 @@
        }
 }

+function f_vty_transceive_match_regex(TELNETasp_PT pt, charstring cmd, 
charstring regex, integer groupno) return charstring
+{
+       var charstring resp := f_vty_transceive_ret(pt, cmd);
+       return regexp(resp, regex, groupno);
+}
+
+function f_vty_transceive_match_regexp_retry(TELNETasp_PT pt, charstring cmd, 
charstring regex,
+                                            integer groupno, integer 
num_attempts, float retry_delay) return charstring
+{
+        while (num_attempts > 0) {
+               var charstring ret := f_vty_transceive_match_regex(pt, cmd, 
regex, groupno);
+               if (ret != "") {
+                       return ret;
+               }
+               f_sleep(retry_delay);
+               num_attempts := num_attempts - 1;
+       }
+
+       setverdict(fail, "No matching VTY response for regular expression '", 
regex,
+                  "' after ", num_attempts, " attempts." );
+       mtc.stop;
+}

 }

--
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Gerrit-Project: osmo-ttcn3-hacks
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I308ddb06e440c165fe1e73fe2c1fb78be2e1d510
Gerrit-Change-Number: 11763
Gerrit-PatchSet: 1
Gerrit-Owner: Stefan Sperling <ssperl...@sysmocom.de>