[Tarantool-patches] [PATCH 3/4] test: enable luajit-tap:gh-4427-ffi-sandwich tests

[Vladislav Shpilevoy]

Hi!

>>>  if (NOT ${PROJECT_BINARY_DIR} STREQUAL ${PROJECT_SOURCE_DIR})
>>> diff --git a/test/app-tap/gh-4427-ffi-sandwich.test.lua b/test/app-tap/gh-4427-ffi-sandwich.test.lua
>>> new file mode 100755
>>> index 000000000..602af88d4
>>> --- /dev/null
>>> +++ b/test/app-tap/gh-4427-ffi-sandwich.test.lua
>>> @@ -0,0 +1,30 @@
>>> +#!/usr/bin/env tarantool
>>> +
>>> +local tap = require('tap')
>>> +
>>> +local test = tap.test('gh-4427-ffi-sandwich')
>>> +
>>> +local cmd = string.gsub(
>>> +  'LUA_CPATH=$/?.so LD_LIBRARY_PATH=$ tarantool 2>&1 $/test.lua %d %d',
>>> +  '%$', os.getenv('BUILDDIR') .. '/test/luajit-tap/gh-4427-ffi-sandwich')
>>> +
>>> +local checks = {
>>> +  { hotloop = 1, trigger = 1, success = true  },
>>> +  { hotloop = 1, trigger = 2, success = false },
>>
>> Why hotloop is needed, if it is always 1?
> 
> I decided to localize instance configuration values and make an explicit
> hotloop parameter. Since the result of the tests depends on hotloop and
> trigger values ratio, it seems more convenient for further maintainence
> to store these params nearby each other.

After the private talk I know that hotloop is some kind of thing affecting
when to start recording a trace. It is worth leaving a comment on that.
And on what is trigger (about this I still don't know).

>>> +}
>>> +
>>> +test:plan(#checks)
>>> +
>>> +for _, ch in pairs(checks) do
>>> +  local res
>>> +  local proc = io.popen(cmd:format(ch.hotloop, ch.trigger))
>>> +  for s in proc:lines('*l') do res = s end
>>
>> What is '*l'?
> 
> Considering the doc[1] this option makes <lines> iterator read the
> stream line by line (the options <lines> passes to its iterator function
> are exactly the same as read accepts).

In the [1] I see that lines() does not take any arguments. file:read()
does. file:lines() does not. Even for file:read() '*l' is default and
can be omitted.

>>> +  assert(res, 'proc:lines failed')
>>> +  if ch.success then
>>> +    test:is(tonumber(res), ch.hotloop + ch.trigger + 1)
>>> +  else
>>> +    test:is(res, 'Lua VM re-entrancy is detected while executing the trace')
>>> +  end
>>> +end
>>> +
>>> +os.exit(test:check() and 0 or 1)
>>
>> Oh God. So luajit already contains cyclic dependencies. It stores suite.ini
>> file in its test folder, which of course is useless for the luajit alone.
>>
>> Since suite.ini file is here, why do you need to run tests from there in such
>> a complex way? Test-run should already be able to peek tests from there (and
>> it does). It probably does not work for your test only because you put it into
>> a folder. I propose you to flatten it, like it is done for function1.test.lua.
>> You still can keep issue name in form of 'gh-####-' in file names to keep them
>> related. They would be
>>
>>     gh-4427-ffi-sandwich.test.lua
>>     gh-4427-ffi-sandwich.c
>>
>> And after build:
>>
>> +   gh-4427-ffi.sandwich.so/.dylib
>>
>> Then you don't a need separate file in app-tap.
> 
> A separate file in app-tap is a runner for the chunk in luajit-tap
> tests. Since I need to test a platform failure, I don't know other way
> than run one Lua script via io.popen from another one.
> 
> So if my math is OK we still have two Lua chunks and a C one:
> * the Lua runner with io.popen and output analyzer
> * the Lua script to be run by Tarantool instance
> * the Dynamic library to be required by the latter Lua script and to be
>   build from the corresponding C file
> 
> Could you please clarify your proposal a bit if I'm wrong or missing
> something?

The problem is that you have one test located in 2 folders and 3 files
now. I propose to make it just 3 files. We never do any test hierarchies.
Also test-run does not support nested folders with tests.

Strictly speaking, you can make it 2 files: C and Lua. In Lua file you
do io.popen on self with an argument, which would mean the file was started
not by test-run, and which would launch the 'platform failure test'.

In that way you will have all test code located in one place (not counting
C file).

    if arg[3] == 'do_test' then
        jit.opt, C, print, ...
        os.exit()
    end

    -- arg[1] - tarantool, arg[2] - this file
    io.popen(string.format('%s %s ...', arg[1], arg[2], 'do_test'))

    test:is(...)
    ...

> [1]: https://www.lua.org/manual/5.1/manual.html#pdf-file:read