Cluster helper does not save artifacts

[locker]

Create the test test/box-luatest/failing_test.lua in the Tarantool repository:

local cbuilder = require('luatest.cbuilder')
local cluster = require('luatest.cluster')
local t = require('luatest')

local g = t.group()

g.before_all(function(cg)
    local config = cbuilder:new()
        :add_instance('test', {})
        :config()
    cg.cluster = cluster.new(config)
    cg.cluster:start()
end)

g.after_all(function(cg)
    cg.cluster:drop()
end)

g.test_fail = function(cg)
    cg.cluster.test:exec(function()
        t.assert(false)
    end)
end

Run it:

cd test
. <(./test-run.py --env)
luatest -v box-luatest/failing_test.lua

The test fails but no artifacts are saved (/tmp/t/artifacts directory doesn't exist).

Note that the luatest.server helper saves artifacts on failure.