Re[2]: [tarantool-patches] Re: [PATCH v2 4/5] test: use wait_cond to check follow status

["Sergei Voronezhskii" <sergw@tarantool.org>]

>Понедельник, 29 октября 2018, 13:41 +03:00 от Alexander Turenko <alexander.turenko@tarantool.org>:
>
>> >> If `test_run:wait_cond()` found a not 'follow` status it returns true.
>> >> Which immediately causes an error.
>> >> 
>> >> Fixes #3734
>> >> Part of #2436, #3232
>> >> ---
>> >>  test/replication/misc.result   | 17 +++++++++++------
>> >>  test/replication/misc.test.lua | 15 +++++++++------
>> >>  2 files changed, 20 insertions(+), 12 deletions(-)
>> >> 
>> >
>> >> diff --git a/test/replication/misc.test.lua b/test/replication/misc.test.lua
>> >> index 06ad974db..3866eb3ac 100644
>> >> --- a/test/replication/misc.test.lua
>> >> +++ b/test/replication/misc.test.lua
>> >> @@ -53,15 +53,18 @@ fiber=require('fiber')
>> >>  box.cfg{replication_timeout = 0.01, replication_connect_timeout=0.01}
>> >>  _ = box.schema.space.create('test_timeout'):create_index('pk')
>> >>  test_run:cmd("setopt delimiter ';'")
>> >> +function wait_follow(replicaA, replicaB)
>> >> +    return test_run:wait_cond(function()
>> >> +        return replicaA.status ~= 'follow' or replicaB.status ~= 'follow'
>> >> +    end, 0.01)
>> >> +end ;
>> >>  function test_timeout()
>> >>      for i = 0, 99 do 
>> >> +        local replicaA = box.info.replication[1].upstream or box.info.replication[2].upstream
>> >> +        local replicaB = box.info.replication[3].upstream or box.info.replication[2].upstream
>> >>          box.space.test_timeout:replace({1})
>> >> -        fiber.sleep(0.005)
>> >> -        local rinfo = box.info.replication
>> >> -        if rinfo[1].upstream and rinfo[1].upstream.status ~= 'follow' or
>> >> -           rinfo[2].upstream and rinfo[2].upstream.status ~= 'follow' or
>> >> -           rinfo[3].upstream and rinfo[3].upstream.status ~= 'follow' then
>> >> -            return error('Replication broken')
>> >> +        if wait_follow(replicaA, replicaB) then
>> >> +            return error(box.info.replication)
>> >
>> >AFAIU, this test case checks that replicas do not leave from 'follow'
>> >state even for a short time period. We should wait for 'follow' state
>> >before the loop and perform some amount of attemps to catch an another
>> >state. I don't sure, though. Georgy should draw the line.
>> >
>> >I still think correction of test cases is a developer responsibility. If
>> >you want to do it, please, discuss it with the author before. This will
>> >save us some time we spend now on those extra review iterations.
>>
>> We discussed with Georgy how to do it:
>> function test_timeout()
>>     local replicaA = box.info.replication[1].upstream or box.info.replication[2].upstream
>>     local replicaB = box.info.replication[3].upstream or box.info.replication[2].upstream
>>     local follows = test_run:wait_cond(function()
>>         return replicaA.status == 'follow' or replicaB.status == 'follow'
>>     end, 0.1)
>>     if not follows then error('replicas not in follow status') end
>>     for i = 0, 99 do
>>         box.space.test_timeout:replace({1})
>>         if wait_follow(replicaA, replicaB) then
>>             return error(box.info.replication)
>>         end
>>     end
>>     return true
>> end ;
>> 
>> Branch was updated.
>
>Now I understand the approach. It looks good. I think it should be
>commented inside the test, because it is counter-intuitive that wait_xxx
>function returns true when something went wrong.

Updated wait_follow with comment:
-- The wait_cond checking the function in loop while it returns false.
-- It returns true if replicas status changed from follow state.
-- Which immediately causes an error

>WBR, Alexander Turenko.


-- 
Sergei Voronezhskii