Not require own test helper when running tests

> Fow what test/helper.lua is needed?

Luatest automatically requires `test/helper.lua` file if it's present.
Usually, it is used to configure luatest or run any bootstrap code.

> What's the problem?

To run tarantool functional tests we use the test-run framework [1].
test-run has an integration with luatest (uses luatest as a submodule)
and allows us to run tarantool functional tests written in the luatest
approach. Most of the such tests can be run via luatest directly, but
test-run is used to run all types of tarantool tests at the same time
(diff, python, app, luatest).

When test-run works, it tunes some environment variables for own needs
and sets LUA_PATH to something like this:

    LUA_PATH='<...>/tarantool/?/init.lua;<...>/tarantool/?.lua;\
        <...>/tarantool/test-run/lib/luatest/?/init.lua;\
        <...>/tarantool/test-run/lib/luatest/?.lua;;'

The tarantool tests don't have own `test/helper.lua` file and this file
is required from the luatest submodule of test-run in accordance with
the configured LUA_PATH variable, which is obviously wrong.

> What's the solution?

The simplest way to resolve this issue is to move `test/helper.lua` to
`test/helpers/general.lua` to not auto-require it while running tests.

Actually, there is no reason to have `test/helper.lua` in luatest. I can
assume it was added to run unit tests with `shuffle = 'group'`. But we
can run unit tests with the `--shuffle group` option and have the same
effect.

[1] https://github.com/tarantool/test-run

Closes #306

Author: ylobankov

.github/workflows/test_on_push.yaml

@@ -33,4 +33,4 @@ jobs:
         run: make lint
 
       - name: Run tests
-        run: bin/luatest -v
+        run: bin/luatest -v --shuffle group

CMakeLists.txt

@@ -60,7 +60,7 @@ add_custom_target(doc
 )
 
 add_custom_target(lint DEPENDS bootstrap COMMAND .rocks/bin/luacheck .)
-add_custom_target(selftest DEPENDS bootstrap COMMAND bin/luatest)
+add_custom_target(selftest DEPENDS bootstrap COMMAND bin/luatest --shuffle group)
 
 add_custom_target(test_with_coverage_report
   DEPENDS bootstrap

test/assertions_test.lua

@@ -1,7 +1,7 @@
 local t = require('luatest')
 local g = t.group()
 
-local helper = require('test.helper')
+local helper = require('test.helpers.general')
 
 g.test_custom_errors = function()
     local function assert_no_exception(fn)

test/autorequire_luatest_test.lua

@@ -4,7 +4,7 @@ local t = require('luatest')
 local g = t.group()
 local Server = t.Server
 
-local root = fio.dirname(fio.dirname(fio.abspath(package.search('test.helper'))))
+local root = fio.dirname(fio.abspath('test.helpers'))
 local datadir = fio.pathjoin(root, 'tmp', 'luatest_module')
 local command = fio.pathjoin(root, 'test', 'server_instance.lua')
 

test/boxcfg_interaction_test.lua

@@ -4,7 +4,7 @@ local t = require('luatest')
 local g = t.group()
 local Server = t.Server
 
-local root = fio.dirname(fio.dirname(fio.abspath(package.search('test.helper'))))
+local root = fio.dirname(fio.abspath('test.helpers'))
 local datadir = fio.pathjoin(root, 'tmp', 'boxcfg_interaction')
 local command = fio.pathjoin(root, 'test', 'server_instance.lua')
 

test/capturing_test.lua

@@ -1,7 +1,7 @@
 local t = require('luatest')
 local g = t.group()
 
-local helper = require('test.helper')
+local helper = require('test.helpers.general')
 local Capture = require('luatest.capture')
 local capture = Capture:new()
 

test/helper.lua renamed to test/helpers/general.lua

@@ -2,8 +2,6 @@ local t = require('luatest')
 local Runner = require('luatest.runner')
 local utils = require('luatest.utils')
 
-t.configure({shuffle = 'group'})
-
 local helper = {}
 
 function helper.run_suite(load_tests, args)

test/hooks_test.lua

@@ -2,7 +2,7 @@ local t = require('luatest')
 local g = t.group()
 
 local Capture = require('luatest.capture')
-local helper = require('test.helper')
+local helper = require('test.helpers.general')
 
 g.test_hooks = function()
     local hooks = {}

test/luatest_test.lua

@@ -1,7 +1,7 @@
 local t = require('luatest')
 local g = t.group()
 
-local helper = require('test.helper')
+local helper = require('test.helpers.general')
 
 g.test_assert_returns_velue = function()
     t.assert_equals(t.assert(1), 1)

test/luaunit/assertions_error_test.lua

@@ -1,7 +1,7 @@
 local t = require('luatest')
 local g = t.group()
 
-local helper = require('test.helper')
+local helper = require('test.helpers.general')
 local assert_failure = helper.assert_failure
 local assert_failure_equals = helper.assert_failure_equals