test: update compat options tests with server:exec

Before the change all tarantool.compat options' tests were running on
the same instance, and because luatest uses multiple threads, they could
interfere with compat configuration at the same time as other test
checks default behavior. This could cause such tests to flack.

Now all options' tests are being run in a separate instance via
server:exec().

Closes #8033

NO_DOC=test fix
NO_CHANGELOG=test fix

test/app-luatest/gh_3012_yaml_prettier_multiline_output_test.lua

-local compat = require('tarantool').compat
-local yaml = require('yaml')
+local server = require('luatest.server')
 local t = require('luatest')
 local g = t.group()
 
-g.test_encode = function()
+local function server_test_encode()
+    local compat = require('tarantool').compat
+    local yaml = require('yaml')
+    local t = require('luatest')
+
     local str = 'Title: xxx\n - Item 1\n - Item 2\n'
     local old_res = '--- "Title: xxx\\n - Item 1\\n - Item 2\\n"\n...\n'
     local new_res = '--- |\n  Title: xxx\n   - Item 1\n   - Item 2\n...\n'
@@ -15,3 +18,10 @@ g.test_encode = function()
     t.assert_equals(yaml.encode(str), old_res)
     compat.yaml_pretty_multiline = 'default'
 end
+
+g.test_encode = function()
+    g.server = server:new{alias = 'default'}
+    g.server:start()
+    g.server:exec(server_test_encode)
+    g.server:stop()
+end

test/app-luatest/gh_6200_lua_cjson_escapes_slash_test.lua

-local compat = require('tarantool').compat
-local json = require('json')
-local popen = require('popen')
-local clock = require('clock')
+local server = require('luatest.server')
 local t = require('luatest')
-local g = t.group()
 
-g.test_json_encode = function()
+local function server_test_json_encode()
+    local compat = require('tarantool').compat
+    local json = require('json')
+    local t = require('luatest')
+
     -- Test that '/' is escaped with default setting.
     t.assert_equals(json.encode({url = 'https://srv:7777'}),
                     '{"url":"https:\\/\\/srv:7777"}')
@@ -44,7 +44,11 @@ g.test_json_encode = function()
                     [["\/home\/user\/tarantool"]])
 end
 
-g.test_json_new_encode = function()
+local function server_test_json_new_encode()
+    local compat = require('tarantool').compat
+    local json = require('json')
+    local t = require('luatest')
+
     compat.json_escape_forward_slash = 'old'
     -- Test that '/' is escaped with 'old' setting.
     t.assert_equals(json.encode('/'), [["\/"]])
@@ -67,7 +71,11 @@ end
 
 -- log.info in json format mode uses internal encoder that takes msgpuck
 -- char2escape table, while mp_char2escape is changed by compat.
-g.test_mp_encode = function()
+local function popen_test_mp_encode()
+    local popen = require('popen')
+    local clock = require('clock')
+    local t = require('luatest')
+
     -- Start external tarantool session.
     local TARANTOOL_PATH = arg[-1]
     local cmd = TARANTOOL_PATH .. ' -i 2>&1'
@@ -117,3 +125,18 @@ g.test_mp_encode = function()
 
     ph:close()
 end
+
+local tests = {
+    server_test_json_encode,
+    server_test_json_new_encode,
+    popen_test_mp_encode,
+}
+
+local g = t.group('pgroup', t.helpers.matrix{test_func = tests})
+
+g.test_json_encode = function(cg)
+    local s = server:new{alias = 'default'}
+    s:start()
+    s:exec(cg.params.test_func)
+    s:stop()
+end

test/app-luatest/gh_7746_fiber_channel_close_test.lua

-local compat = require('tarantool').compat
+local server = require('luatest.server')
 local t = require('luatest')
-local g = t.group()
-local fiber = require('fiber')
 
-g.test_channel_close_default = function()
+local function server_test_channel_close_default()
+    local fiber = require('fiber')
+    local t = require('luatest')
+
     -- No graceful close (old) by default.
     local ch = fiber.channel(10)
     ch:put('one')
@@ -15,48 +16,40 @@ g.test_channel_close_default = function()
     t.assert_equals(ch:get(), nil)
 end
 
-g.test_channel_close_old = function()
-    compat.fiber_channel_close_mode = 'old'
-    local ch = fiber.channel(10)
-    ch:put('one')
-    ch:put('two')
-    t.assert_equals(ch:get(), 'one')
-    ch:close()
-    t.assert(ch:is_closed())
-    t.assert_not(ch:put('three'))
-    t.assert_equals(ch:get(), nil)
-end
+local function server_test_channel_close(mode)
+    local compat = require('tarantool').compat
+    local fiber = require('fiber')
+    local t = require('luatest')
 
-g.test_channel_close_new = function()
     -- Graceful close (new) selected.
-    compat.fiber_channel_close_mode = 'new'
+    compat.fiber_channel_close_mode = mode
     local ch = fiber.channel(10)
     ch:put('one')
     ch:put('two')
+    ch:put('three')
+
+    t.assert_equals(ch:get(), 'one')
     ch:close()
 
     t.assert(ch:is_closed())
-    t.assert_not(ch:put('three'))
+    t.assert_not(ch:put('four'))
 
-    t.assert_equals(ch:get(), 'one')
-    t.assert(ch:is_closed())
+    if mode == 'new' then
+        t.assert_equals(ch:get(), 'two')
+        t.assert(ch:is_closed())
 
-    t.assert_equals(ch:get(), 'two')
-    t.assert(ch:is_closed())
+        t.assert_equals(ch:get(), 'three')
+        t.assert(ch:is_closed())
+    end
 
     t.assert_equals(ch:get(), nil)
 end
 
-g.test_close_graceful_on_empty = function()
-    compat.fiber_channel_close_mode = 'new'
-    local ch = fiber.channel(10)
-    ch:put('one')
-    ch:get()
-    ch:close()
-    t.assert(ch:is_closed())
-end
+local server_test_close_reader_payload = function(mode)
+    local compat = require('tarantool').compat
+    local fiber = require('fiber')
+    local t = require('luatest')
 
-local test_close_reader_payload = function(mode)
     compat.fiber_channel_close_mode = mode
     local ch = fiber.channel(0)
     local reader = fiber.new(function()
@@ -86,15 +79,11 @@ local test_close_reader_payload = function(mode)
     t.assert(status, err)
 end
 
-g.test_close_reader_old = function()
-    test_close_reader_payload('old')
-end
-
-g.test_close_reader_new = function()
-    test_close_reader_payload('new')
-end
+local server_test_close_writer_payload = function(mode)
+    local compat = require('tarantool').compat
+    local fiber = require('fiber')
+    local t = require('luatest')
 
-local test_close_writer_payload = function(mode)
     compat.fiber_channel_close_mode = mode
     local ch = fiber.channel(0)
     local writer = fiber.new(function()
@@ -124,10 +113,19 @@ local test_close_writer_payload = function(mode)
     t.assert(status, err)
 end
 
-g.test_close_writer_old = function()
-    test_close_writer_payload('old')
-end
+local tests = {
+    server_test_channel_close,
+    server_test_channel_close_default,
+    server_test_close_writer_payload,
+    server_test_close_reader_payload,
+}
+
+local g = t.group('pgroup', t.helpers.matrix{test_func = tests,
+                                             mode = {'new', 'old'}})
 
-g.test_close_writer_new = function()
-    test_close_writer_payload('new')
+g.test_fiber_close = function(cg)
+    local s = server:new{alias = 'default'}
+    s:start()
+    s:exec(cg.params.test_func, {cg.params.mode})
+    s:stop()
 end