aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/test/cases/relations_test.rb
blob: bc6cac0c6c39a7ef3cb8fec95c27068d0921adbd (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
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
require "cases/helper"
require 'models/tag'
require 'models/tagging'
require 'models/post'
require 'models/topic'
require 'models/comment'
require 'models/author'
require 'models/entrant'
require 'models/developer'
require 'models/reply'
require 'models/company'
require 'models/bird'
require 'models/car'
require 'models/engine'
require 'models/tyre'
require 'models/minivan'


class RelationTest < ActiveRecord::TestCase
  fixtures :authors, :topics, :entrants, :developers, :companies, :developers_projects, :accounts, :categories, :categorizations, :posts, :comments,
    :tags, :taggings, :cars, :minivans

  def test_do_not_double_quote_string_id
    van = Minivan.last
    assert van
    assert_equal van.id, Minivan.where(:minivan_id => van).to_a.first.minivan_id
  end

  def test_do_not_double_quote_string_id_with_array
    van = Minivan.last
    assert van
    assert_equal van, Minivan.where(:minivan_id => [van]).to_a.first
  end

  def test_bind_values
    relation = Post.all
    assert_equal [], relation.bind_values

    relation2 = relation.bind 'foo'
    assert_equal %w{ foo }, relation2.bind_values
    assert_equal [], relation.bind_values
  end

  def test_two_scopes_with_includes_should_not_drop_any_include
    car = Car.incl_engines.incl_tyres.first
    assert_no_queries { car.tyres.length }
    assert_no_queries { car.engines.length }
  end

  def test_dynamic_finder
    x = Post.where('author_id = ?', 1)
    assert x.klass.respond_to?(:find_by_id), '@klass should handle dynamic finders'
  end

  def test_multivalue_where
    posts = Post.where('author_id = ? AND id = ?', 1, 1)
    assert_equal 1, posts.to_a.size
  end

  def test_scoped
    topics = Topic.all
    assert_kind_of ActiveRecord::Relation, topics
    assert_equal 4, topics.size
  end

  def test_to_json
    assert_nothing_raised  { Bird.all.to_json }
    assert_nothing_raised  { Bird.all.to_a.to_json }
  end

  def test_to_yaml
    assert_nothing_raised  { Bird.all.to_yaml }
    assert_nothing_raised  { Bird.all.to_a.to_yaml }
  end

  def test_to_xml
    assert_nothing_raised  { Bird.all.to_xml }
    assert_nothing_raised  { Bird.all.to_a.to_xml }
  end

  def test_scoped_all
    topics = Topic.all.to_a
    assert_kind_of Array, topics
    assert_no_queries { assert_equal 4, topics.size }
  end

  def test_loaded_all
    topics = Topic.all

    assert_queries(1) do
      2.times { assert_equal 4, topics.to_a.size }
    end

    assert topics.loaded?
  end

  def test_scoped_first
    topics = Topic.all.order('id ASC')

    assert_queries(1) do
      2.times { assert_equal "The First Topic", topics.first.title }
    end

    assert ! topics.loaded?
  end

  def test_loaded_first
    topics = Topic.all.order('id ASC')

    assert_queries(1) do
      topics.to_a # force load
      2.times { assert_equal "The First Topic", topics.first.title }
    end

    assert topics.loaded?
  end

  def test_reload
    topics = Topic.all

    assert_queries(1) do
      2.times { topics.to_a }
    end

    assert topics.loaded?

    original_size = topics.to_a.size
    Topic.create! :title => 'fake'

    assert_queries(1) { topics.reload }
    assert_equal original_size + 1, topics.size
    assert topics.loaded?
  end

  def test_finding_with_subquery
    relation = Topic.where(:approved => true)
    assert_equal relation.to_a, Topic.select('*').from(relation).to_a
    assert_equal relation.to_a, Topic.select('subquery.*').from(relation).to_a
    assert_equal relation.to_a, Topic.select('a.*').from(relation, :a).to_a
  end

  def test_finding_with_conditions
    assert_equal ["David"], Author.where(:name => 'David').map(&:name)
    assert_equal ['Mary'],  Author.where(["name = ?", 'Mary']).map(&:name)
    assert_equal ['Mary'],  Author.where("name = ?", 'Mary').map(&:name)
  end

  def test_finding_with_order
    topics = Topic.order('id')
    assert_equal 4, topics.to_a.size
    assert_equal topics(:first).title, topics.first.title
  end


  def test_finding_with_arel_order
    topics = Topic.order(Topic.arel_table[:id].asc)
    assert_equal 4, topics.to_a.size
    assert_equal topics(:first).title, topics.first.title
  end
  
  def test_finding_with_assoc_order
    topics = Topic.order(:id => :desc)
    assert_equal 4, topics.to_a.size
    assert_equal topics(:fourth).title, topics.first.title
  end
  
  def test_finding_with_reverted_assoc_order
    topics = Topic.order(:id => :asc).reverse_order
    assert_equal 4, topics.to_a.size
    assert_equal topics(:fourth).title, topics.first.title
  end
  
  def test_raising_exception_on_invalid_hash_params
    assert_raise(ArgumentError) { Topic.order(:name, "id DESC", :id => :DeSc) }
  end

  def test_finding_last_with_arel_order
    topics = Topic.order(Topic.arel_table[:id].asc)
    assert_equal topics(:fourth).title, topics.last.title
  end

  def test_finding_with_order_concatenated
    topics = Topic.order('title').order('author_name')
    assert_equal 4, topics.to_a.size
    assert_equal topics(:fourth).title, topics.first.title
  end

  def test_finding_with_reorder
    topics = Topic.order('author_name').order('title').reorder('id').to_a
    topics_titles = topics.map{ |t| t.title }
    assert_equal ['The First Topic', 'The Second Topic of the day', 'The Third Topic of the day', 'The Fourth Topic of the day'], topics_titles
  end

  def test_finding_with_order_and_take
    entrants = Entrant.order("id ASC").limit(2).to_a

    assert_equal 2, entrants.size
    assert_equal entrants(:first).name, entrants.first.name
  end

  def test_finding_with_cross_table_order_and_limit
    tags = Tag.includes(:taggings).
              order("tags.name asc", "taggings.taggable_id asc", "REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").
              limit(1).to_a
    assert_equal 1, tags.length
  end

  def test_finding_with_complex_order_and_limit
    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").limit(1).to_a
    assert_equal 1, tags.length
  end

  def test_finding_with_complex_order
    tags = Tag.includes(:taggings).references(:taggings).order("REPLACE('abc', taggings.taggable_type, taggings.taggable_type)").to_a
    assert_equal 3, tags.length
  end

  def test_finding_with_order_limit_and_offset
    entrants = Entrant.order("id ASC").limit(2).offset(1)

    assert_equal 2, entrants.to_a.size
    assert_equal entrants(:second).name, entrants.first.name

    entrants = Entrant.order("id ASC").limit(2).offset(2)
    assert_equal 1, entrants.to_a.size
    assert_equal entrants(:third).name, entrants.first.name
  end

  def test_finding_with_group
    developers = Developer.group("salary").select("salary").to_a
    assert_equal 4, developers.size
    assert_equal 4, developers.map(&:salary).uniq.size
  end

  def test_select_with_block
    even_ids = Developer.all.select {|d| d.id % 2 == 0 }.map(&:id)
    assert_equal [2, 4, 6, 8, 10], even_ids.sort
  end

  def test_none
    assert_no_queries do
      assert_equal [], Developer.none
      assert_equal [], Developer.all.none
    end
  end

  def test_none_chainable
    assert_no_queries do
      assert_equal [], Developer.none.where(:name => 'David')
    end
  end

  def test_none_chainable_to_existing_scope_extension_method
    assert_no_queries do
      assert_equal 1, Topic.anonymous_extension.none.one
    end
  end

  def test_none_chained_to_methods_firing_queries_straight_to_db
    assert_no_queries do
      assert_equal [],    Developer.none.pluck(:id) # => uses select_all
      assert_equal 0,     Developer.none.delete_all
      assert_equal 0,     Developer.none.update_all(:name => 'David')
      assert_equal 0,     Developer.none.delete(1)
      assert_equal false, Developer.none.exists?(1)
    end
  end

  def test_null_relation_content_size_methods
    assert_no_queries do
      assert_equal 0,     Developer.none.size
      assert_equal 0,     Developer.none.count
      assert_equal true,  Developer.none.empty?
      assert_equal false, Developer.none.any?
      assert_equal false, Developer.none.many?
    end
  end

  def test_null_relation_calculations_methods
    assert_no_queries do
      assert_equal 0,     Developer.none.count
      assert_equal nil,   Developer.none.calculate(:average, 'salary')
    end
  end

  def test_null_relation_metadata_methods
    assert_equal "", Developer.none.to_sql
    assert_equal({}, Developer.none.where_values_hash)
  end

  def test_joins_with_nil_argument
    assert_nothing_raised { DependentFirm.joins(nil).first }
  end

  def test_finding_with_hash_conditions_on_joined_table
    firms = DependentFirm.joins(:account).where({:name => 'RailsCore', :accounts => { :credit_limit => 55..60 }}).to_a
    assert_equal 1, firms.size
    assert_equal companies(:rails_core), firms.first
  end

  def test_find_all_with_join
    developers_on_project_one = Developer.joins('LEFT JOIN developers_projects ON developers.id = developers_projects.developer_id').
      where('project_id=1').to_a

    assert_equal 3, developers_on_project_one.length
    developer_names = developers_on_project_one.map { |d| d.name }
    assert developer_names.include?('David')
    assert developer_names.include?('Jamis')
  end

  def test_find_on_hash_conditions
    assert_equal Topic.all.merge!(:where => {:approved => false}).to_a, Topic.where({ :approved => false }).to_a
  end

  def test_joins_with_string_array
    person_with_reader_and_post = Post.joins([
        "INNER JOIN categorizations ON categorizations.post_id = posts.id",
        "INNER JOIN categories ON categories.id = categorizations.category_id AND categories.type = 'SpecialCategory'"
      ]
    ).to_a
    assert_equal 1, person_with_reader_and_post.size
  end

  def test_scoped_responds_to_delegated_methods
    relation = Topic.all

    ["map", "uniq", "sort", "insert", "delete", "update"].each do |method|
      assert_respond_to relation, method, "Topic.all should respond to #{method.inspect}"
    end
  end

  def test_respond_to_delegates_to_relation
    relation = Topic.all
    fake_arel = Struct.new(:responds) {
      def respond_to? method, access = false
        responds << [method, access]
      end
    }.new []

    relation.extend(Module.new { attr_accessor :arel })
    relation.arel = fake_arel

    relation.respond_to?(:matching_attributes)
    assert_equal [:matching_attributes, false], fake_arel.responds.first

    fake_arel.responds = []
    relation.respond_to?(:matching_attributes, true)
    assert_equal [:matching_attributes, true], fake_arel.responds.first
  end

  def test_respond_to_dynamic_finders
    relation = Topic.all

    ["find_by_title", "find_by_title_and_author_name", "find_or_create_by_title", "find_or_initialize_by_title_and_author_name"].each do |method|
      assert_respond_to relation, method, "Topic.all should respond to #{method.inspect}"
    end
  end

  def test_respond_to_class_methods_and_scopes
    assert Topic.all.respond_to?(:by_lifo)
  end

  def test_find_with_readonly_option
    Developer.all.each { |d| assert !d.readonly? }
    Developer.all.readonly.each { |d| assert d.readonly? }
  end

  def test_eager_association_loading_of_stis_with_multiple_references
    authors = Author.eager_load(:posts => { :special_comments => { :post => [ :special_comments, :very_special_comment ] } }).
      order('comments.body, very_special_comments_posts.body').where('posts.id = 4').to_a

    assert_equal [authors(:david)], authors
    assert_no_queries do
      authors.first.posts.first.special_comments.first.post.special_comments
      authors.first.posts.first.special_comments.first.post.very_special_comment
    end
  end

  def test_find_with_preloaded_associations
    assert_queries(2) do
      posts = Post.preload(:comments).order('posts.id')
      assert posts.first.comments.first
    end

    assert_queries(2) do
      posts = Post.preload(:comments).order('posts.id')
      assert posts.first.comments.first
    end

    assert_queries(2) do
      posts = Post.preload(:author).order('posts.id')
      assert posts.first.author
    end

    assert_queries(2) do
      posts = Post.preload(:author).order('posts.id')
      assert posts.first.author
    end

    assert_queries(3) do
      posts = Post.preload(:author, :comments).order('posts.id')
      assert posts.first.author
      assert posts.first.comments.first
    end
  end

  def test_find_with_included_associations
    assert_queries(2) do
      posts = Post.includes(:comments).order('posts.id')
      assert posts.first.comments.first
    end

    assert_queries(2) do
      posts = Post.all.includes(:comments).order('posts.id')
      assert posts.first.comments.first
    end

    assert_queries(2) do
      posts = Post.includes(:author).order('posts.id')
      assert posts.first.author
    end

    assert_queries(3) do
      posts = Post.includes(:author, :comments).order('posts.id')
      assert posts.first.author
      assert posts.first.comments.first
    end
  end

  def test_default_scope_with_conditions_string
    assert_equal Developer.where(name: 'David').map(&:id).sort, DeveloperCalledDavid.all.map(&:id).sort
    assert_nil DeveloperCalledDavid.create!.name
  end

  def test_default_scope_with_conditions_hash
    assert_equal Developer.where(name: 'Jamis').map(&:id).sort, DeveloperCalledJamis.all.map(&:id).sort
    assert_equal 'Jamis', DeveloperCalledJamis.create!.name
  end

  def test_default_scoping_finder_methods
    developers = DeveloperCalledDavid.order('id').map(&:id).sort
    assert_equal Developer.where(name: 'David').map(&:id).sort, developers
  end

  def test_loading_with_one_association
    posts = Post.preload(:comments)
    post = posts.find { |p| p.id == 1 }
    assert_equal 2, post.comments.size
    assert post.comments.include?(comments(:greetings))

    post = Post.where("posts.title = 'Welcome to the weblog'").preload(:comments).first
    assert_equal 2, post.comments.size
    assert post.comments.include?(comments(:greetings))

    posts = Post.preload(:last_comment)
    post = posts.find { |p| p.id == 1 }
    assert_equal Post.find(1).last_comment, post.last_comment
  end

  def test_loading_with_one_association_with_non_preload
    posts = Post.eager_load(:last_comment).order('comments.id DESC')
    post = posts.find { |p| p.id == 1 }
    assert_equal Post.find(1).last_comment, post.last_comment
  end

  def test_dynamic_find_by_attributes
    david = authors(:david)
    author = Author.preload(:taggings).find_by_id(david.id)
    expected_taggings = taggings(:welcome_general, :thinking_general)

    assert_no_queries do
      assert_equal expected_taggings, author.taggings.uniq.sort_by { |t| t.id }
    end

    authors = Author.all
    assert_equal david, authors.find_by_id_and_name(david.id, david.name)
    assert_equal david, authors.find_by_id_and_name!(david.id, david.name)
  end

  def test_dynamic_find_by_attributes_bang
    author = Author.all.find_by_id!(authors(:david).id)
    assert_equal "David", author.name

    assert_raises(ActiveRecord::RecordNotFound) { Author.all.find_by_id_and_name!(20, 'invalid') }
  end

  def test_find_id
    authors = Author.all

    david = authors.find(authors(:david).id)
    assert_equal 'David', david.name

    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find('42') }
  end

  def test_find_ids
    authors = Author.order('id ASC')

    results = authors.find(authors(:david).id, authors(:mary).id)
    assert_kind_of Array, results
    assert_equal 2, results.size
    assert_equal 'David', results[0].name
    assert_equal 'Mary', results[1].name
    assert_equal results, authors.find([authors(:david).id, authors(:mary).id])

    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find(authors(:david).id, '42') }
    assert_raises(ActiveRecord::RecordNotFound) { authors.find(['42', 43]) }
  end

  def test_find_in_empty_array
    authors = Author.all.where(:id => [])
    assert_blank authors.to_a
  end

  def test_where_with_ar_object
    author = Author.first
    authors = Author.all.where(:id => author)
    assert_equal 1, authors.to_a.length
  end

  def test_find_with_list_of_ar
    author = Author.first
    authors = Author.find([author])
    assert_equal author, authors.first
  end

  class Mary < Author; end

  def test_find_by_classname
    Author.create!(:name => Mary.name)
    assert_equal 1, Author.where(:name => Mary).size
  end

  def test_find_by_id_with_list_of_ar
    author = Author.first
    authors = Author.find_by_id([author])
    assert_equal author, authors
  end

  def test_find_all_using_where_twice_should_or_the_relation
    david = authors(:david)
    relation = Author.unscoped
    relation = relation.where(:name => david.name)
    relation = relation.where(:name => 'Santiago')
    relation = relation.where(:id => david.id)
    assert_equal [], relation.to_a
  end

  def test_multi_where_ands_queries
    relation = Author.unscoped
    david = authors(:david)
    sql = relation.where(:name => david.name).where(:name => 'Santiago').to_sql
    assert_match('AND', sql)
  end

  def test_find_all_with_multiple_should_use_and
    david = authors(:david)
    relation = [
      { :name => david.name },
      { :name => 'Santiago' },
      { :name => 'tenderlove' },
    ].inject(Author.unscoped) do |memo, param|
      memo.where(param)
    end
    assert_equal [], relation.to_a
  end

  def test_find_all_using_where_with_relation
    david = authors(:david)
    # switching the lines below would succeed in current rails
    # assert_queries(2) {
    assert_queries(1) {
      relation = Author.where(:id => Author.where(:id => david.id))
      assert_equal [david], relation.to_a
    }
  end

  def test_find_all_using_where_with_relation_and_alternate_primary_key
    cool_first = minivans(:cool_first)
    # switching the lines below would succeed in current rails
    # assert_queries(2) {
    assert_queries(1) {
      relation = Minivan.where(:minivan_id => Minivan.where(:name => cool_first.name))
      assert_equal [cool_first], relation.to_a
    }
  end

  def test_find_all_using_where_with_relation_does_not_alter_select_values
    david = authors(:david)

    subquery = Author.where(:id => david.id)

    assert_queries(1) {
      relation = Author.where(:id => subquery)
      assert_equal [david], relation.to_a
    }

    assert_equal 0, subquery.select_values.size
  end

  def test_find_all_using_where_with_relation_with_joins
    david = authors(:david)
    assert_queries(1) {
      relation = Author.where(:id => Author.joins(:posts).where(:id => david.id))
      assert_equal [david], relation.to_a
    }
  end


  def test_find_all_using_where_with_relation_with_select_to_build_subquery
    david = authors(:david)
    assert_queries(1) {
      relation = Author.where(:name => Author.where(:id => david.id).select(:name))
      assert_equal [david], relation.to_a
    }
  end

  def test_exists
    davids = Author.where(:name => 'David')
    assert davids.exists?
    assert davids.exists?(authors(:david).id)
    assert ! davids.exists?(authors(:mary).id)
    assert ! davids.exists?("42")
    assert ! davids.exists?(42)
    assert ! davids.exists?(davids.new)

    fake  = Author.where(:name => 'fake author')
    assert ! fake.exists?
    assert ! fake.exists?(authors(:david).id)
  end

  def test_last
    authors = Author.all
    assert_equal authors(:bob), authors.last
  end

  def test_destroy_all
    davids = Author.where(:name => 'David')

    # Force load
    assert_equal [authors(:david)], davids.to_a
    assert davids.loaded?

    assert_difference('Author.count', -1) { davids.destroy_all }

    assert_equal [], davids.to_a
    assert davids.loaded?
  end

  def test_delete_all
    davids = Author.where(:name => 'David')

    assert_difference('Author.count', -1) { davids.delete_all }
    assert ! davids.loaded?
  end

  def test_delete_all_loaded
    davids = Author.where(:name => 'David')

    # Force load
    assert_equal [authors(:david)], davids.to_a
    assert davids.loaded?

    assert_difference('Author.count', -1) { davids.delete_all }

    assert_equal [], davids.to_a
    assert davids.loaded?
  end

  def test_delete_all_limit_error
    assert_raises(ActiveRecord::ActiveRecordError) { Author.limit(10).delete_all }
  end

  def test_select_takes_a_variable_list_of_args
    david = developers(:david)

    developer = Developer.where(id: david.id).select(:name, :salary).first
    assert_equal david.name, developer.name
    assert_equal david.salary, developer.salary
  end

  def test_select_argument_error
    assert_raises(ArgumentError) { Developer.select }
  end

  def test_relation_merging
    devs = Developer.where("salary >= 80000").merge(Developer.limit(2)).merge(Developer.order('id ASC').where("id < 3"))
    assert_equal [developers(:david), developers(:jamis)], devs.to_a

    dev_with_count = Developer.limit(1).merge(Developer.order('id DESC')).merge(Developer.select('developers.*'))
    assert_equal [developers(:poor_jamis)], dev_with_count.to_a
  end

  def test_relation_merging_with_arel_equalities_keeps_last_equality
    devs = Developer.where(Developer.arel_table[:salary].eq(80000)).merge(
      Developer.where(Developer.arel_table[:salary].eq(9000))
    )
    assert_equal [developers(:poor_jamis)], devs.to_a
  end

  def test_relation_merging_with_arel_equalities_keeps_last_equality_with_non_attribute_left_hand
    salary_attr = Developer.arel_table[:salary]
    devs = Developer.where(
      Arel::Nodes::NamedFunction.new('abs', [salary_attr]).eq(80000)
    ).merge(
      Developer.where(
        Arel::Nodes::NamedFunction.new('abs', [salary_attr]).eq(9000)
      )
    )
    assert_equal [developers(:poor_jamis)], devs.to_a
  end

  def test_relation_merging_with_eager_load
    relations = []
    relations << Post.order('comments.id DESC').merge(Post.eager_load(:last_comment)).merge(Post.all)
    relations << Post.eager_load(:last_comment).merge(Post.order('comments.id DESC')).merge(Post.all)

    relations.each do |posts|
      post = posts.find { |p| p.id == 1 }
      assert_equal Post.find(1).last_comment, post.last_comment
    end
  end

  def test_relation_merging_with_locks
    devs = Developer.lock.where("salary >= 80000").order("id DESC").merge(Developer.limit(2))
    assert_present devs.locked
  end

  def test_relation_merging_with_preload
    [Post.all.merge(Post.preload(:author)), Post.preload(:author).merge(Post.all)].each do |posts|
      assert_queries(2) { assert posts.first.author }
    end
  end

  def test_relation_merging_with_joins
    comments = Comment.joins(:post).where(:body => 'Thank you for the welcome').merge(Post.where(:body => 'Such a lovely day'))
    assert_equal 1, comments.count
  end

  def test_relation_merging_with_association
    assert_queries(2) do  # one for loading post, and another one merged query
      post = Post.where(:body => 'Such a lovely day').first
      comments = Comment.where(:body => 'Thank you for the welcome').merge(post.comments)
      assert_equal 1, comments.count
    end
  end

  def test_count
    posts = Post.all

    assert_equal 11, posts.count
    assert_equal 11, posts.count(:all)
    assert_equal 11, posts.count(:id)

    assert_equal 1, posts.where('comments_count > 1').count
    assert_equal 9, posts.where(:comments_count => 0).count
  end

  def test_count_with_distinct
    posts = Post.all

    assert_equal 3, posts.count(:comments_count, :distinct => true)
    assert_equal 11, posts.count(:comments_count, :distinct => false)

    assert_equal 3, posts.select(:comments_count).count(:distinct => true)
    assert_equal 11, posts.select(:comments_count).count(:distinct => false)
  end

  def test_count_explicit_columns
    Post.update_all(:comments_count => nil)
    posts = Post.all

    assert_equal [0], posts.select('comments_count').where('id is not null').group('id').order('id').count.values.uniq
    assert_equal 0, posts.where('id is not null').select('comments_count').count

    assert_equal 11, posts.select('comments_count').count('id')
    assert_equal 0, posts.select('comments_count').count
    assert_equal 0, posts.count(:comments_count)
    assert_equal 0, posts.count('comments_count')
  end

  def test_multiple_selects
    post = Post.all.select('comments_count').select('title').order("id ASC").first
    assert_equal "Welcome to the weblog", post.title
    assert_equal 2, post.comments_count
  end

  def test_size
    posts = Post.all

    assert_queries(1) { assert_equal 11, posts.size }
    assert ! posts.loaded?

    best_posts = posts.where(:comments_count => 0)
    best_posts.to_a # force load
    assert_no_queries { assert_equal 9, best_posts.size }
  end

  def test_size_with_limit
    posts = Post.limit(10)

    assert_queries(1) { assert_equal 10, posts.size }
    assert ! posts.loaded?

    best_posts = posts.where(:comments_count => 0)
    best_posts.to_a # force load
    assert_no_queries { assert_equal 9, best_posts.size }
  end

  def test_size_with_zero_limit
    posts = Post.limit(0)

    assert_no_queries { assert_equal 0, posts.size }
    assert ! posts.loaded?

    posts.to_a # force load
    assert_no_queries { assert_equal 0, posts.size }
  end

  def test_empty_with_zero_limit
    posts = Post.limit(0)

    assert_no_queries { assert_equal true, posts.empty? }
    assert ! posts.loaded?
  end

  def test_count_complex_chained_relations
    posts = Post.select('comments_count').where('id is not null').group("author_id").where("comments_count > 0")

    expected = { 1 => 2 }
    assert_equal expected, posts.count
  end

  def test_empty
    posts = Post.all

    assert_queries(1) { assert_equal false, posts.empty? }
    assert ! posts.loaded?

    no_posts = posts.where(:title => "")
    assert_queries(1) { assert_equal true, no_posts.empty? }
    assert ! no_posts.loaded?

    best_posts = posts.where(:comments_count => 0)
    best_posts.to_a # force load
    assert_no_queries { assert_equal false, best_posts.empty? }
  end

  def test_empty_complex_chained_relations
    posts = Post.select("comments_count").where("id is not null").group("author_id").where("comments_count > 0")

    assert_queries(1) { assert_equal false, posts.empty? }
    assert ! posts.loaded?

    no_posts = posts.where(:title => "")
    assert_queries(1) { assert_equal true, no_posts.empty? }
    assert ! no_posts.loaded?
  end

  def test_any
    posts = Post.all

    # This test was failing when run on its own (as opposed to running the entire suite).
    # The second line in the assert_queries block was causing visit_Arel_Attributes_Attribute
    # in Arel::Visitors::ToSql to trigger a SHOW TABLES query. Running that line here causes
    # the SHOW TABLES result to be cached so we don't have to do it again in the block.
    #
    # This is obviously a rubbish fix but it's the best I can come up with for now...
    posts.where(:id => nil).any?

    assert_queries(3) do
      assert posts.any? # Uses COUNT()
      assert ! posts.where(:id => nil).any?

      assert posts.any? {|p| p.id > 0 }
      assert ! posts.any? {|p| p.id <= 0 }
    end

    assert posts.loaded?
  end

  def test_many
    posts = Post.all

    assert_queries(2) do
      assert posts.many? # Uses COUNT()
      assert posts.many? {|p| p.id > 0 }
      assert ! posts.many? {|p| p.id < 2 }
    end

    assert posts.loaded?
  end

  def test_many_with_limits
    posts = Post.all

    assert posts.many?
    assert ! posts.limit(1).many?
  end

  def test_build
    posts = Post.all

    post = posts.new
    assert_kind_of Post, post
  end

  def test_scoped_build
    posts = Post.where(:title => 'You told a lie')

    post = posts.new
    assert_kind_of Post, post
    assert_equal 'You told a lie', post.title
  end

  def test_create
    birds = Bird.all

    sparrow = birds.create
    assert_kind_of Bird, sparrow
    assert !sparrow.persisted?

    hen = birds.where(:name => 'hen').create
    assert hen.persisted?
    assert_equal 'hen', hen.name
  end

  def test_create_bang
    birds = Bird.all

    assert_raises(ActiveRecord::RecordInvalid) { birds.create! }

    hen = birds.where(:name => 'hen').create!
    assert_kind_of Bird, hen
    assert hen.persisted?
    assert_equal 'hen', hen.name
  end

  def test_first_or_create
    parrot = Bird.where(:color => 'green').first_or_create(:name => 'parrot')
    assert_kind_of Bird, parrot
    assert parrot.persisted?
    assert_equal 'parrot', parrot.name
    assert_equal 'green', parrot.color

    same_parrot = Bird.where(:color => 'green').first_or_create(:name => 'parakeet')
    assert_kind_of Bird, same_parrot
    assert same_parrot.persisted?
    assert_equal parrot, same_parrot
  end

  def test_first_or_create_with_no_parameters
    parrot = Bird.where(:color => 'green').first_or_create
    assert_kind_of Bird, parrot
    assert !parrot.persisted?
    assert_equal 'green', parrot.color
  end

  def test_first_or_create_with_block
    parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parrot' }
    assert_kind_of Bird, parrot
    assert parrot.persisted?
    assert_equal 'green', parrot.color
    assert_equal 'parrot', parrot.name

    same_parrot = Bird.where(:color => 'green').first_or_create { |bird| bird.name = 'parakeet' }
    assert_equal parrot, same_parrot
  end

  def test_first_or_create_with_array
    several_green_birds = Bird.where(:color => 'green').first_or_create([{:name => 'parrot'}, {:name => 'parakeet'}])
    assert_kind_of Array, several_green_birds
    several_green_birds.each { |bird| assert bird.persisted? }

    same_parrot = Bird.where(:color => 'green').first_or_create([{:name => 'hummingbird'}, {:name => 'macaw'}])
    assert_kind_of Bird, same_parrot
    assert_equal several_green_birds.first, same_parrot
  end

  def test_first_or_create_bang_with_valid_options
    parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parrot')
    assert_kind_of Bird, parrot
    assert parrot.persisted?
    assert_equal 'parrot', parrot.name
    assert_equal 'green', parrot.color

    same_parrot = Bird.where(:color => 'green').first_or_create!(:name => 'parakeet')
    assert_kind_of Bird, same_parrot
    assert same_parrot.persisted?
    assert_equal parrot, same_parrot
  end

  def test_first_or_create_bang_with_invalid_options
    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!(:pirate_id => 1) }
  end

  def test_first_or_create_bang_with_no_parameters
    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create! }
  end

  def test_first_or_create_bang_with_valid_block
    parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parrot' }
    assert_kind_of Bird, parrot
    assert parrot.persisted?
    assert_equal 'green', parrot.color
    assert_equal 'parrot', parrot.name

    same_parrot = Bird.where(:color => 'green').first_or_create! { |bird| bird.name = 'parakeet' }
    assert_equal parrot, same_parrot
  end

  def test_first_or_create_bang_with_invalid_block
    assert_raise(ActiveRecord::RecordInvalid) do
      Bird.where(:color => 'green').first_or_create! { |bird| bird.pirate_id = 1 }
    end
  end

  def test_first_or_create_with_valid_array
    several_green_birds = Bird.where(:color => 'green').first_or_create!([{:name => 'parrot'}, {:name => 'parakeet'}])
    assert_kind_of Array, several_green_birds
    several_green_birds.each { |bird| assert bird.persisted? }

    same_parrot = Bird.where(:color => 'green').first_or_create!([{:name => 'hummingbird'}, {:name => 'macaw'}])
    assert_kind_of Bird, same_parrot
    assert_equal several_green_birds.first, same_parrot
  end

  def test_first_or_create_with_invalid_array
    assert_raises(ActiveRecord::RecordInvalid) { Bird.where(:color => 'green').first_or_create!([ {:name => 'parrot'}, {:pirate_id => 1} ]) }
  end

  def test_first_or_initialize
    parrot = Bird.where(:color => 'green').first_or_initialize(:name => 'parrot')
    assert_kind_of Bird, parrot
    assert !parrot.persisted?
    assert parrot.valid?
    assert parrot.new_record?
    assert_equal 'parrot', parrot.name
    assert_equal 'green', parrot.color
  end

  def test_first_or_initialize_with_no_parameters
    parrot = Bird.where(:color => 'green').first_or_initialize
    assert_kind_of Bird, parrot
    assert !parrot.persisted?
    assert !parrot.valid?
    assert parrot.new_record?
    assert_equal 'green', parrot.color
  end

  def test_first_or_initialize_with_block
    parrot = Bird.where(:color => 'green').first_or_initialize { |bird| bird.name = 'parrot' }
    assert_kind_of Bird, parrot
    assert !parrot.persisted?
    assert parrot.valid?
    assert parrot.new_record?
    assert_equal 'green', parrot.color
    assert_equal 'parrot', parrot.name
  end

  def test_find_or_create_by
    assert_nil Bird.find_by(name: 'bob')

    bird = Bird.find_or_create_by(name: 'bob')
    assert bird.persisted?

    assert_equal bird, Bird.find_or_create_by(name: 'bob')
  end

  def test_find_or_create_by_with_create_with
    assert_nil Bird.find_by(name: 'bob')

    bird = Bird.create_with(color: 'green').find_or_create_by(name: 'bob')
    assert bird.persisted?
    assert_equal 'green', bird.color

    assert_equal bird, Bird.create_with(color: 'blue').find_or_create_by(name: 'bob')
  end

  def test_find_or_create_by!
    assert_raises(ActiveRecord::RecordInvalid) { Bird.find_or_create_by!(color: 'green') }
  end

  def test_find_or_initialize_by
    assert_nil Bird.find_by(name: 'bob')

    bird = Bird.find_or_initialize_by(name: 'bob')
    assert bird.new_record?
    bird.save!

    assert_equal bird, Bird.find_or_initialize_by(name: 'bob')
  end

  def test_explicit_create_scope
    hens = Bird.where(:name => 'hen')
    assert_equal 'hen', hens.new.name

    hens = hens.create_with(:name => 'cock')
    assert_equal 'cock', hens.new.name
  end

  def test_except
    relation = Post.where(:author_id => 1).order('id ASC').limit(1)
    assert_equal [posts(:welcome)], relation.to_a

    author_posts = relation.except(:order, :limit)
    assert_equal Post.where(:author_id => 1).to_a, author_posts.to_a

    all_posts = relation.except(:where, :order, :limit)
    assert_equal Post.all, all_posts
  end

  def test_only
    relation = Post.where(:author_id => 1).order('id ASC').limit(1)
    assert_equal [posts(:welcome)], relation.to_a

    author_posts = relation.only(:where)
    assert_equal Post.where(:author_id => 1).to_a, author_posts.to_a

    all_posts = relation.only(:limit)
    assert_equal Post.limit(1).to_a.first, all_posts.first
  end

  def test_anonymous_extension
    relation = Post.where(:author_id => 1).order('id ASC').extending do
      def author
        'lifo'
      end
    end

    assert_equal "lifo", relation.author
    assert_equal "lifo", relation.limit(1).author
  end

  def test_named_extension
    relation = Post.where(:author_id => 1).order('id ASC').extending(Post::NamedExtension)
    assert_equal "lifo", relation.author
    assert_equal "lifo", relation.limit(1).author
  end

  def test_order_by_relation_attribute
    assert_equal Post.order(Post.arel_table[:title]).to_a, Post.order("title").to_a
  end

  def test_default_scope_order_with_scope_order
    assert_equal 'honda', CoolCar.order_using_new_style.limit(1).first.name
    assert_equal 'honda', FastCar.order_using_new_style.limit(1).first.name
  end

  def test_order_using_scoping
    car1 = CoolCar.order('id DESC').scoping do
      CoolCar.all.merge!(:order => 'id asc').first
    end
    assert_equal 'honda', car1.name

    car2 = FastCar.order('id DESC').scoping do
      FastCar.all.merge!(:order => 'id asc').first
    end
    assert_equal 'honda', car2.name
  end

  def test_unscoped_block_style
    assert_equal 'honda', CoolCar.unscoped { CoolCar.order_using_new_style.limit(1).first.name}
    assert_equal 'honda', FastCar.unscoped { FastCar.order_using_new_style.limit(1).first.name}
  end

  def test_intersection_with_array
    relation = Author.where(:name => "David")
    rails_author = relation.first

    assert_equal [rails_author], [rails_author] & relation
    assert_equal [rails_author], relation & [rails_author]
  end

  def test_primary_key
    assert_equal "id", Post.all.primary_key
  end

  def test_eager_loading_with_conditions_on_joins
    scope = Post.includes(:comments)

    # This references the comments table, and so it should cause the comments to be eager
    # loaded via a JOIN, rather than by subsequent queries.
    scope = scope.joins(
      Post.arel_table.create_join(
        Post.arel_table,
        Post.arel_table.create_on(Comment.arel_table[:id].eq(3))
      )
    )

    assert_deprecated do
      assert scope.eager_loading?
    end
  end

  def test_ordering_with_extra_spaces
    assert_equal authors(:david), Author.order('id DESC , name DESC').last
  end

  def test_update_all_with_blank_argument
    assert_raises(ArgumentError) { Comment.update_all({}) }
  end

  def test_update_all_with_joins
    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id)
    count    = comments.count

    assert_equal count, comments.update_all(:post_id => posts(:thinking).id)
    assert_equal posts(:thinking), comments(:greetings).post
  end

  def test_update_all_with_joins_and_limit
    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).limit(1)
    assert_equal 1, comments.update_all(:post_id => posts(:thinking).id)
  end

  def test_update_all_with_joins_and_limit_and_order
    comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).order('comments.id').limit(1)
    assert_equal 1, comments.update_all(:post_id => posts(:thinking).id)
    assert_equal posts(:thinking), comments(:greetings).post
    assert_equal posts(:welcome),  comments(:more_greetings).post
  end

  def test_update_all_with_joins_and_offset
    all_comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id)
    count        = all_comments.count
    comments     = all_comments.offset(1)

    assert_equal count - 1, comments.update_all(:post_id => posts(:thinking).id)
  end

  def test_update_all_with_joins_and_offset_and_order
    all_comments = Comment.joins(:post).where('posts.id' => posts(:welcome).id).order('posts.id', 'comments.id')
    count        = all_comments.count
    comments     = all_comments.offset(1)

    assert_equal count - 1, comments.update_all(:post_id => posts(:thinking).id)
    assert_equal posts(:thinking), comments(:more_greetings).post
    assert_equal posts(:welcome),  comments(:greetings).post
  end

  def test_uniq
    tag1 = Tag.create(:name => 'Foo')
    tag2 = Tag.create(:name => 'Foo')

    query = Tag.select(:name).where(:id => [tag1.id, tag2.id])

    assert_equal ['Foo', 'Foo'], query.map(&:name)
    assert_sql(/DISTINCT/) do
      assert_equal ['Foo'], query.uniq.map(&:name)
    end
    assert_sql(/DISTINCT/) do
      assert_equal ['Foo'], query.uniq(true).map(&:name)
    end
    assert_equal ['Foo', 'Foo'], query.uniq(true).uniq(false).map(&:name)
  end

  def test_references_triggers_eager_loading
    scope = Post.includes(:comments)
    assert !scope.eager_loading?
    assert scope.references(:comments).eager_loading?
  end

  def test_references_doesnt_trigger_eager_loading_if_reference_not_included
    scope = Post.references(:comments)
    assert !scope.eager_loading?
  end

  def test_automatically_added_where_references
    scope = Post.where(:comments => { :body => "Bla" })
    assert_equal ['comments'], scope.references_values

    scope = Post.where('comments.body' => 'Bla')
    assert_equal ['comments'], scope.references_values
  end

  def test_automatically_added_having_references
    scope = Post.having(:comments => { :body => "Bla" })
    assert_equal ['comments'], scope.references_values

    scope = Post.having('comments.body' => 'Bla')
    assert_equal ['comments'], scope.references_values
  end

  def test_automatically_added_order_references
    scope = Post.order('comments.body')
    assert_equal ['comments'], scope.references_values

    scope = Post.order('comments.body', 'yaks.body')
    assert_equal ['comments', 'yaks'], scope.references_values

    # Don't infer yaks, let's not go down that road again...
    scope = Post.order('comments.body, yaks.body')
    assert_equal ['comments'], scope.references_values

    scope = Post.order('comments.body asc')
    assert_equal ['comments'], scope.references_values

    scope = Post.order('foo(comments.body)')
    assert_equal [], scope.references_values
  end

  def test_presence
    topics = Topic.all

    # the first query is triggered because there are no topics yet.
    assert_queries(1) { assert topics.present? }

    # checking if there are topics is used before you actually display them,
    # thus it shouldn't invoke an extra count query.
    assert_no_queries { assert topics.present? }
    assert_no_queries { assert !topics.blank? }

    # shows count of topics and loops after loading the query should not trigger extra queries either.
    assert_no_queries { topics.size }
    assert_no_queries { topics.length }
    assert_no_queries { topics.each }

    # count always trigger the COUNT query.
    assert_queries(1) { topics.count }

    assert topics.loaded?
  end

  test "find_by with hash conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by(author_id: 2)
  end

  test "find_by with non-hash conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by("author_id = 2")
  end

  test "find_by with multi-arg conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by('author_id = ?', 2)
  end

  test "find_by returns nil if the record is missing" do
    assert_equal nil, Post.all.find_by("1 = 0")
  end

  test "find_by doesn't have implicit ordering" do
    assert_sql(/^((?!ORDER).)*$/) { Post.find_by(author_id: 2) }
  end

  test "find_by! with hash conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by!(author_id: 2)
  end

  test "find_by! with non-hash conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by!("author_id = 2")
  end

  test "find_by! with multi-arg conditions returns the first matching record" do
    assert_equal posts(:eager_other), Post.order(:id).find_by!('author_id = ?', 2)
  end

  test "find_by! doesn't have implicit ordering" do
    assert_sql(/^((?!ORDER).)*$/) { Post.find_by!(author_id: 2) }
  end

  test "find_by! raises RecordNotFound if the record is missing" do
    assert_raises(ActiveRecord::RecordNotFound) do
      Post.all.find_by!("1 = 0")
    end
  end

  test "loaded relations cannot be mutated by multi value methods" do
    relation = Post.all
    relation.to_a

    assert_raises(ActiveRecord::ImmutableRelation) do
      relation.where! 'foo'
    end
  end

  test "loaded relations cannot be mutated by single value methods" do
    relation = Post.all
    relation.to_a

    assert_raises(ActiveRecord::ImmutableRelation) do
      relation.limit! 5
    end
  end

  test "loaded relations cannot be mutated by merge!" do
    relation = Post.all
    relation.to_a

    assert_raises(ActiveRecord::ImmutableRelation) do
      relation.merge! where: 'foo'
    end
  end

  test "loaded relations cannot be mutated by extending!" do
    relation = Post.all
    relation.to_a

    assert_raises(ActiveRecord::ImmutableRelation) do
      relation.extending! Module.new
    end
  end

  test "relations show the records in #inspect" do
    relation = Post.limit(2)
    assert_equal "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>", relation.inspect
  end

  test "relations limit the records in #inspect at 10" do
    relation = Post.limit(11)
    assert_equal "#<ActiveRecord::Relation [#{Post.limit(10).map(&:inspect).join(', ')}, ...]>", relation.inspect
  end

  test "already-loaded relations don't perform a new query in #inspect" do
    relation = Post.limit(2)
    relation.to_a

    expected = "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>"

    assert_no_queries do
      assert_equal expected, relation.inspect
    end
  end

  test 'using a custom table affects the wheres' do
    table_alias = Post.arel_table.alias('omg_posts')

    relation = ActiveRecord::Relation.new Post, table_alias
    relation.where!(:foo => "bar")

    node = relation.arel.constraints.first.grep(Arel::Attributes::Attribute).first
    assert_equal table_alias, node.relation
  end

  test '#load' do
    relation = Post.all
    assert_queries(1) do
      assert_equal relation, relation.load
    end
    assert_no_queries { relation.to_a }
  end
end