luacheck: fix warnings in test/engine

Closes #5458

Reviewed-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Reviewed-by: Igor Munkin <imun@tarantool.org>

Co-authored-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Co-authored-by: Igor Munkin <imun@tarantool.org>

.luacheckrc

@@ -33,7 +33,7 @@ exclude_files = {
     "test-run/**/*.lua",
     "test/app/*.test.lua",
     "test/box/*.test.lua",
-    "test/engine/**/*.lua",
+    "test/engine/*.test.lua",
     "test/engine_long/**/*.lua",
     "test/luajit-tap/**/*.lua",
     "test/replication/**/*.lua",

test/engine/box.lua

 #!/usr/bin/env tarantool
-os = require('os')
-
-local vinyl = {
-    threads = 3,
-    range_size=1024*64,
-    page_size=1024,
-}
+local os = require('os')
 
 box.cfg{
     listen              = os.getenv("LISTEN"),

test/engine/conflict.lua

 
-function test_conflict()
+local function test_conflict()
     local test_run = require('test_run')
     local inspector = test_run.new()
     local engine = inspector:get_cfg('engine')
 
     local s = box.schema.space.create('tester', {engine=engine});
-    local i = s:create_index('test_index', {type = 'tree', parts = {1, 'string'}});
+    s:create_index('test_index', {type = 'tree', parts = {1, 'string'}});
 
     local commits = 0
     local function conflict()
@@ -16,10 +16,14 @@ function test_conflict()
     end;
 
     local fiber = require('fiber');
-    local f0 = fiber.create(conflict);
-    local f1 = fiber.create(conflict); -- conflict
+    fiber.create(conflict);
+    fiber.create(conflict); -- conflict
     fiber.sleep(0);
 
     s:drop();
     return commits
 end
+
+return {
+    test_conflict = test_conflict;
+}

test/engine/conflict.result

-dofile('conflict.lua')
+conflict = require('conflict')
 ---
 ...
-test_conflict()
+conflict.test_conflict()
 ---
 - 2
 ...

test/engine/conflict.test.lua

 
-dofile('conflict.lua')
+conflict = require('conflict')
 
-test_conflict()
+conflict.test_conflict()