aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/test/cases/transactions_test.rb
blob: 791b895d02fc78a22842b319d73af90f45dabd5c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
require "cases/helper"
require 'models/topic'
require 'models/reply'
require 'models/developer'
require 'models/computer'
require 'models/book'
require 'models/author'
require 'models/post'
require 'models/movie'

class TransactionTest < ActiveRecord::TestCase
  self.use_transactional_tests = false
  fixtures :topics, :developers, :authors, :posts

  def setup
    @first, @second = Topic.find(1, 2).sort_by(&:id)
  end

  def test_persisted_in_a_model_with_custom_primary_key_after_failed_save
    movie = Movie.create
    assert !movie.persisted?
  end

  def test_raise_after_destroy
    assert_not @first.frozen?

    assert_raises(RuntimeError) {
      Topic.transaction do
        @first.destroy
        assert @first.frozen?
        raise
      end
    }

    assert @first.reload
    assert_not @first.frozen?
  end

  def test_successful
    Topic.transaction do
      @first.approved  = true
      @second.approved = false
      @first.save
      @second.save
    end

    assert Topic.find(1).approved?, "First should have been approved"
    assert !Topic.find(2).approved?, "Second should have been unapproved"
  end

  def transaction_with_return
    Topic.transaction do
      @first.approved  = true
      @second.approved = false
      @first.save
      @second.save
      return
    end
  end

  def test_add_to_null_transaction
    topic = Topic.new
    topic.add_to_transaction
  end

  def test_successful_with_return
    committed = false

    Topic.connection.class_eval do
      alias :real_commit_db_transaction :commit_db_transaction
      define_method(:commit_db_transaction) do
        committed = true
        real_commit_db_transaction
      end
    end

    transaction_with_return
    assert committed

    assert Topic.find(1).approved?, "First should have been approved"
    assert !Topic.find(2).approved?, "Second should have been unapproved"
  ensure
    Topic.connection.class_eval do
      remove_method :commit_db_transaction
      alias :commit_db_transaction :real_commit_db_transaction rescue nil
    end
  end

  def test_number_of_transactions_in_commit
    num = nil

    Topic.connection.class_eval do
      alias :real_commit_db_transaction :commit_db_transaction
      define_method(:commit_db_transaction) do
        num = transaction_manager.open_transactions
        real_commit_db_transaction
      end
    end

    Topic.transaction do
      @first.approved  = true
      @first.save!
    end

    assert_equal 0, num
  ensure
    Topic.connection.class_eval do
      remove_method :commit_db_transaction
      alias :commit_db_transaction :real_commit_db_transaction rescue nil
    end
  end

  def test_successful_with_instance_method
    @first.transaction do
      @first.approved  = true
      @second.approved = false
      @first.save
      @second.save
    end

    assert Topic.find(1).approved?, "First should have been approved"
    assert !Topic.find(2).approved?, "Second should have been unapproved"
  end

  def test_failing_on_exception
    begin
      Topic.transaction do
        @first.approved  = true
        @second.approved = false
        @first.save
        @second.save
        raise "Bad things!"
      end
    rescue
      # caught it
    end

    assert @first.approved?, "First should still be changed in the objects"
    assert !@second.approved?, "Second should still be changed in the objects"

    assert !Topic.find(1).approved?, "First shouldn't have been approved"
    assert Topic.find(2).approved?, "Second should still be approved"
  end

  def test_raising_exception_in_callback_rollbacks_in_save
    def @first.after_save_for_transaction
      raise 'Make the transaction rollback'
    end

    @first.approved = true
    e = assert_raises(RuntimeError) { @first.save }
    assert_equal "Make the transaction rollback", e.message
    assert !Topic.find(1).approved?
  end

  def test_rolling_back_in_a_callback_rollbacks_before_save
    def @first.before_save_for_transaction
      raise ActiveRecord::Rollback
    end
    assert !@first.approved

    Topic.transaction do
      @first.approved  = true
      @first.save!
    end
    assert !Topic.find(@first.id).approved?, "Should not commit the approved flag"
  end

  def test_raising_exception_in_nested_transaction_restore_state_in_save
    topic = Topic.new

    def topic.after_save_for_transaction
      raise 'Make the transaction rollback'
    end

    assert_raises(RuntimeError) do
      Topic.transaction { topic.save }
    end

    assert topic.new_record?, "#{topic.inspect} should be new record"
  end

  def test_transaction_state_is_cleared_when_record_is_persisted
    author = Author.create! name: 'foo'
    author.name = nil
    assert_not author.save
    assert_not author.new_record?
  end

  def test_update_should_rollback_on_failure
    author = Author.find(1)
    posts_count = author.posts.size
    assert posts_count > 0
    status = author.update(name: nil, post_ids: [])
    assert !status
    assert_equal posts_count, author.posts.reload.size
  end

  def test_update_should_rollback_on_failure!
    author = Author.find(1)
    posts_count = author.posts.size
    assert posts_count > 0
    assert_raise(ActiveRecord::RecordInvalid) do
      author.update!(name: nil, post_ids: [])
    end
    assert_equal posts_count, author.posts.reload.size
  end

  def test_cancellation_from_returning_false_in_before_filter
    def @first.before_save_for_transaction
      false
    end

    assert_deprecated do
      @first.save
    end
  end

  def test_cancellation_from_before_destroy_rollbacks_in_destroy
    add_cancelling_before_destroy_with_db_side_effect_to_topic @first
    nbooks_before_destroy = Book.count
    status = @first.destroy
    assert !status
    @first.reload
    assert_equal nbooks_before_destroy, Book.count
  end

  %w(validation save).each do |filter|
    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}") do
      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
      nbooks_before_save = Book.count
      original_author_name = @first.author_name
      @first.author_name += '_this_should_not_end_up_in_the_db'
      status = @first.save
      assert !status
      assert_equal original_author_name, @first.reload.author_name
      assert_equal nbooks_before_save, Book.count
    end

    define_method("test_cancellation_from_before_filters_rollbacks_in_#{filter}!") do
      send("add_cancelling_before_#{filter}_with_db_side_effect_to_topic", @first)
      nbooks_before_save = Book.count
      original_author_name = @first.author_name
      @first.author_name += '_this_should_not_end_up_in_the_db'

      begin
        @first.save!
      rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotSaved
      end

      assert_equal original_author_name, @first.reload.author_name
      assert_equal nbooks_before_save, Book.count
    end
  end

  def test_callback_rollback_in_create
    topic = Class.new(Topic) {
      def after_create_for_transaction
        raise 'Make the transaction rollback'
      end
    }

    new_topic = topic.new(:title                => "A new topic",
                          :author_name          => "Ben",
                          :author_email_address => "ben@example.com",
                          :written_on           => "2003-07-16t15:28:11.2233+01:00",
                          :last_read            => "2004-04-15",
                          :bonus_time           => "2005-01-30t15:28:00.00+01:00",
                          :content              => "Have a nice day",
                          :approved             => false)

    new_record_snapshot = !new_topic.persisted?
    id_present = new_topic.has_attribute?(Topic.primary_key)
    id_snapshot = new_topic.id

    # Make sure the second save gets the after_create callback called.
    2.times do
      new_topic.approved = true
      e = assert_raises(RuntimeError) { new_topic.save }
      assert_equal "Make the transaction rollback", e.message
      assert_equal new_record_snapshot, !new_topic.persisted?, "The topic should have its old persisted value"
      assert_equal id_snapshot, new_topic.id, "The topic should have its old id"
      assert_equal id_present, new_topic.has_attribute?(Topic.primary_key)
    end
  end

  def test_callback_rollback_in_create_with_record_invalid_exception
    topic = Class.new(Topic) {
      def after_create_for_transaction
        raise ActiveRecord::RecordInvalid.new(Author.new)
      end
    }

    new_topic = topic.create(:title => "A new topic")
    assert !new_topic.persisted?, "The topic should not be persisted"
    assert_nil new_topic.id, "The topic should not have an ID"
  end

  def test_nested_explicit_transactions
    Topic.transaction do
      Topic.transaction do
        @first.approved  = true
        @second.approved = false
        @first.save
        @second.save
      end
    end

    assert Topic.find(1).approved?, "First should have been approved"
    assert !Topic.find(2).approved?, "Second should have been unapproved"
  end

  def test_manually_rolling_back_a_transaction
    Topic.transaction do
      @first.approved  = true
      @second.approved = false
      @first.save
      @second.save

      raise ActiveRecord::Rollback
    end

    assert @first.approved?, "First should still be changed in the objects"
    assert !@second.approved?, "Second should still be changed in the objects"

    assert !Topic.find(1).approved?, "First shouldn't have been approved"
    assert Topic.find(2).approved?, "Second should still be approved"
  end

  def test_invalid_keys_for_transaction
    assert_raise ArgumentError do
      Topic.transaction :nested => true do
      end
    end
  end

  def test_force_savepoint_in_nested_transaction
    Topic.transaction do
      @first.approved = true
      @second.approved = false
      @first.save!
      @second.save!

      begin
        Topic.transaction :requires_new => true do
          @first.happy = false
          @first.save!
          raise
        end
      rescue
      end
    end

    assert @first.reload.approved?
    assert !@second.reload.approved?
  end if Topic.connection.supports_savepoints?

  def test_force_savepoint_on_instance
    @first.transaction do
      @first.approved  = true
      @second.approved = false
      @first.save!
      @second.save!

      begin
        @second.transaction :requires_new => true do
          @first.happy = false
          @first.save!
          raise
        end
      rescue
      end
    end

    assert @first.reload.approved?
    assert !@second.reload.approved?
  end if Topic.connection.supports_savepoints?

  def test_no_savepoint_in_nested_transaction_without_force
    Topic.transaction do
      @first.approved = true
      @second.approved = false
      @first.save!
      @second.save!

      begin
        Topic.transaction do
          @first.approved = false
          @first.save!
          raise
        end
      rescue
      end
    end

    assert !@first.reload.approved?
    assert !@second.reload.approved?
  end if Topic.connection.supports_savepoints?

  def test_many_savepoints
    Topic.transaction do
      @first.content = "One"
      @first.save!

      begin
        Topic.transaction :requires_new => true do
          @first.content = "Two"
          @first.save!

          begin
            Topic.transaction :requires_new => true do
              @first.content = "Three"
              @first.save!

              begin
                Topic.transaction :requires_new => true do
                  @first.content = "Four"
                  @first.save!
                  raise
                end
              rescue
              end

              @three = @first.reload.content
              raise
            end
          rescue
          end

          @two = @first.reload.content
          raise
        end
      rescue
      end

      @one = @first.reload.content
    end

    assert_equal "One", @one
    assert_equal "Two", @two
    assert_equal "Three", @three
  end if Topic.connection.supports_savepoints?

  def test_using_named_savepoints
    Topic.transaction do
      @first.approved  = true
      @first.save!
      Topic.connection.create_savepoint("first")

      @first.approved  = false
      @first.save!
      Topic.connection.rollback_to_savepoint("first")
      assert @first.reload.approved?

      @first.approved  = false
      @first.save!
      Topic.connection.release_savepoint("first")
      assert_not @first.reload.approved?
    end
  end if Topic.connection.supports_savepoints?

  def test_releasing_named_savepoints
    Topic.transaction do
      Topic.connection.create_savepoint("another")
      Topic.connection.release_savepoint("another")

      # The savepoint is now gone and we can't remove it again.
      assert_raises(ActiveRecord::StatementInvalid) do
        Topic.connection.release_savepoint("another")
      end
    end
  end

  def test_savepoints_name
    Topic.transaction do
      assert_nil Topic.connection.current_savepoint_name
      assert_nil Topic.connection.current_transaction.savepoint_name

      Topic.transaction(requires_new: true) do
        assert_equal "active_record_1", Topic.connection.current_savepoint_name
        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name

        Topic.transaction(requires_new: true) do
          assert_equal "active_record_2", Topic.connection.current_savepoint_name
          assert_equal "active_record_2", Topic.connection.current_transaction.savepoint_name
        end

        assert_equal "active_record_1", Topic.connection.current_savepoint_name
        assert_equal "active_record_1", Topic.connection.current_transaction.savepoint_name
      end
    end
  end

  def test_rollback_when_commit_raises
    assert_called(Topic.connection, :begin_db_transaction) do
      Topic.connection.stub(:commit_db_transaction, ->{ raise('OH NOES') }) do
        assert_called(Topic.connection, :rollback_db_transaction) do

          e = assert_raise RuntimeError do
            Topic.transaction do
              # do nothing
            end
          end
          assert_equal 'OH NOES', e.message
        end
      end
    end
  end

  def test_rollback_when_saving_a_frozen_record
    topic = Topic.new(:title => 'test')
    topic.freeze
    e = assert_raise(RuntimeError) { topic.save }
    assert_match(/frozen/i, e.message) # Not good enough, but we can't do much
                                       # about it since there is no specific error
                                       # for frozen objects.
    assert !topic.persisted?, 'not persisted'
    assert_nil topic.id
    assert topic.frozen?, 'not frozen'
  end

  def test_rollback_when_thread_killed
    return if in_memory_db?

    queue = Queue.new
    thread = Thread.new do
      Topic.transaction do
        @first.approved  = true
        @second.approved = false
        @first.save

        queue.push nil
        sleep

        @second.save
      end
    end

    queue.pop
    thread.kill
    thread.join

    assert @first.approved?, "First should still be changed in the objects"
    assert !@second.approved?, "Second should still be changed in the objects"

    assert !Topic.find(1).approved?, "First shouldn't have been approved"
    assert Topic.find(2).approved?, "Second should still be approved"
  end

  def test_restore_active_record_state_for_all_records_in_a_transaction
    topic_without_callbacks = Class.new(ActiveRecord::Base) do
      self.table_name = 'topics'
    end

    topic_1 = Topic.new(:title => 'test_1')
    topic_2 = Topic.new(:title => 'test_2')
    topic_3 = topic_without_callbacks.new(:title => 'test_3')

    Topic.transaction do
      assert topic_1.save
      assert topic_2.save
      assert topic_3.save
      @first.save
      @second.destroy
      assert topic_1.persisted?, 'persisted'
      assert_not_nil topic_1.id
      assert topic_2.persisted?, 'persisted'
      assert_not_nil topic_2.id
      assert topic_3.persisted?, 'persisted'
      assert_not_nil topic_3.id
      assert @first.persisted?, 'persisted'
      assert_not_nil @first.id
      assert @second.destroyed?, 'destroyed'
      raise ActiveRecord::Rollback
    end

    assert !topic_1.persisted?, 'not persisted'
    assert_nil topic_1.id
    assert !topic_2.persisted?, 'not persisted'
    assert_nil topic_2.id
    assert !topic_3.persisted?, 'not persisted'
    assert_nil topic_3.id
    assert @first.persisted?, 'persisted'
    assert_not_nil @first.id
    assert !@second.destroyed?, 'not destroyed'
  end

  def test_restore_frozen_state_after_double_destroy
    topic = Topic.create
    reply = topic.replies.create

    Topic.transaction do
      topic.destroy # calls #destroy on reply (since dependent: destroy)
      reply.destroy

      raise ActiveRecord::Rollback
    end

    assert_not reply.frozen?
    assert_not topic.frozen?
  end

  def test_rollback_of_frozen_records
    topic = Topic.create.freeze
    Topic.transaction do
      topic.destroy
      raise ActiveRecord::Rollback
    end
    assert topic.frozen?, 'frozen'
  end

  def test_rollback_for_freshly_persisted_records
    topic = Topic.create
    Topic.transaction do
      topic.destroy
      raise ActiveRecord::Rollback
    end
    assert topic.persisted?, 'persisted'
  end

  def test_sqlite_add_column_in_transaction
    return true unless current_adapter?(:SQLite3Adapter)

    # Test first if column creation/deletion works correctly when no
    # transaction is in place.
    #
    # We go back to the connection for the column queries because
    # Topic.columns is cached and won't report changes to the DB

    assert_nothing_raised do
      Topic.reset_column_information
      Topic.connection.add_column('topics', 'stuff', :string)
      assert Topic.column_names.include?('stuff')

      Topic.reset_column_information
      Topic.connection.remove_column('topics', 'stuff')
      assert !Topic.column_names.include?('stuff')
    end

    if Topic.connection.supports_ddl_transactions?
      assert_nothing_raised do
        Topic.transaction { Topic.connection.add_column('topics', 'stuff', :string) }
      end
    else
      Topic.transaction do
        assert_raise(ActiveRecord::StatementInvalid) { Topic.connection.add_column('topics', 'stuff', :string) }
        raise ActiveRecord::Rollback
      end
    end
  ensure
    begin
      Topic.connection.remove_column('topics', 'stuff')
    rescue
    ensure
      Topic.reset_column_information
    end
  end

  def test_transactions_state_from_rollback
    connection = Topic.connection
    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction

    assert transaction.open?
    assert !transaction.state.rolledback?
    assert !transaction.state.committed?

    transaction.rollback

    assert transaction.state.rolledback?
    assert !transaction.state.committed?
  end

  def test_transactions_state_from_commit
    connection = Topic.connection
    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction

    assert transaction.open?
    assert !transaction.state.rolledback?
    assert !transaction.state.committed?

    transaction.commit

    assert !transaction.state.rolledback?
    assert transaction.state.committed?
  end

  def test_transaction_rollback_with_primarykeyless_tables
    connection = ActiveRecord::Base.connection
    connection.create_table(:transaction_without_primary_keys, force: true, id: false) do |t|
       t.integer :thing_id
    end

    klass = Class.new(ActiveRecord::Base) do
      self.table_name = 'transaction_without_primary_keys'
      after_commit { } # necessary to trigger the has_transactional_callbacks branch
    end

    assert_no_difference(-> { klass.count }) do
      ActiveRecord::Base.transaction do
        klass.create!
        raise ActiveRecord::Rollback
      end
    end
  ensure
    connection.drop_table 'transaction_without_primary_keys', if_exists: true
  end

  private

  %w(validation save destroy).each do |filter|
    define_method("add_cancelling_before_#{filter}_with_db_side_effect_to_topic") do |topic|
      meta = class << topic; self; end
      meta.send("define_method", "before_#{filter}_for_transaction") do
        Book.create
        throw(:abort)
      end
    end
  end
end

class TransactionsWithTransactionalFixturesTest < ActiveRecord::TestCase
  self.use_transactional_tests = true
  fixtures :topics

  def test_automatic_savepoint_in_outer_transaction
    @first = Topic.find(1)

    begin
      Topic.transaction do
        @first.approved = true
        @first.save!
        raise
      end
    rescue
      assert !@first.reload.approved?
    end
  end

  def test_no_automatic_savepoint_for_inner_transaction
    @first = Topic.find(1)

    Topic.transaction do
      @first.approved = true
      @first.save!

      begin
        Topic.transaction do
          @first.approved = false
          @first.save!
          raise
        end
      rescue
      end
    end

    assert !@first.reload.approved?
  end
end if Topic.connection.supports_savepoints?

if current_adapter?(:PostgreSQLAdapter)
  class ConcurrentTransactionTest < TransactionTest
    # This will cause transactions to overlap and fail unless they are performed on
    # separate database connections.
    unless in_memory_db?
      def test_transaction_per_thread
        threads = 3.times.map do
          Thread.new do
            Topic.transaction do
              topic = Topic.find(1)
              topic.approved = !topic.approved?
              assert topic.save!
              topic.approved = !topic.approved?
              assert topic.save!
            end
            Topic.connection.close
          end
        end

        threads.each(&:join)
      end
    end

    # Test for dirty reads among simultaneous transactions.
    def test_transaction_isolation__read_committed
      # Should be invariant.
      original_salary = Developer.find(1).salary
      temporary_salary = 200000

      assert_nothing_raised do
        threads = (1..3).map do
          Thread.new do
            Developer.transaction do
              # Expect original salary.
              dev = Developer.find(1)
              assert_equal original_salary, dev.salary

              dev.salary = temporary_salary
              dev.save!

              # Expect temporary salary.
              dev = Developer.find(1)
              assert_equal temporary_salary, dev.salary

              dev.salary = original_salary
              dev.save!

              # Expect original salary.
              dev = Developer.find(1)
              assert_equal original_salary, dev.salary
            end
            Developer.connection.close
          end
        end

        # Keep our eyes peeled.
        threads << Thread.new do
          10.times do
            sleep 0.05
            Developer.transaction do
              # Always expect original salary.
              assert_equal original_salary, Developer.find(1).salary
            end
          end
          Developer.connection.close
        end

        threads.each(&:join)
      end

      assert_equal original_salary, Developer.find(1).salary
    end
  end
end