summaryrefslogtreecommitdiff
path: root/test/rubygems/test_gem_resolver.rb
blob: f2469ac70f0f503bf57906475d21a0e6f95d3da1 (plain)
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
# frozen_string_literal: true
require 'rubygems/test_case'

class TestGemResolver < Gem::TestCase

  def setup
    super

    @DR = Gem::Resolver
  end

  def make_dep(name, *req)
    Gem::Dependency.new(name, *req)
  end

  def set(*specs)
    source = Gem::Source.new URI @gem_repo

    specs = specs.map do |spec|
      Gem::Resolver::SpecSpecification.new nil, spec, source
    end

    StaticSet.new(specs)
  end

  def assert_resolves_to expected, resolver
    actual = resolver.resolve

    exp = expected.sort_by { |s| s.full_name }
    act = actual.map { |a| a.spec.spec }.sort_by { |s| s.full_name }

    msg = "Set of gems was not the same: #{exp.map { |x| x.full_name}.inspect} != #{act.map { |x| x.full_name}.inspect}"

    assert_equal exp, act, msg
  rescue Gem::DependencyResolutionError => e
    flunk e.message
  end

  def test_self_compatibility
    assert_same Gem::Resolver, Gem::DependencyResolver
  end

  def test_self_compose_sets_best_set
    best_set = @DR::BestSet.new

    composed = @DR.compose_sets best_set

    assert_equal best_set, composed
  end

  def test_self_compose_sets_multiple
    index_set  = @DR::IndexSet.new
    vendor_set = @DR::VendorSet.new

    composed = @DR.compose_sets index_set, vendor_set

    assert_kind_of Gem::Resolver::ComposedSet, composed

    assert_equal [index_set, vendor_set], composed.sets
  end

  def test_self_compose_sets_nest
    index_set  = @DR::IndexSet.new
    vendor_set = @DR::VendorSet.new

    inner = @DR.compose_sets index_set, vendor_set

    current_set = @DR::CurrentSet.new

    composed = @DR.compose_sets inner, current_set

    assert_kind_of Gem::Resolver::ComposedSet, composed

    assert_equal [index_set, vendor_set, current_set], composed.sets
  end

  def test_self_compose_sets_nil
    index_set  = @DR::IndexSet.new

    composed = @DR.compose_sets index_set, nil

    assert_same index_set, composed

    e = assert_raises ArgumentError do
      @DR.compose_sets nil
    end

    assert_equal 'one set in the composition must be non-nil', e.message
  end

  def test_self_compose_sets_single
    index_set  = @DR::IndexSet.new

    composed = @DR.compose_sets index_set

    assert_same index_set, composed
  end

  def test_requests
    a1 = util_spec 'a', 1, 'b' => 2

    r1 = Gem::Resolver::DependencyRequest.new dep('a', '= 1'), nil

    act = Gem::Resolver::ActivationRequest.new a1, r1, false

    res = Gem::Resolver.new [a1]

    reqs = []

    res.requests a1, act, reqs

    assert_equal ['b (= 2)'], reqs.map { |req| req.to_s }
  end

  def test_requests_development
    a1 = util_spec 'a', 1, 'b' => 2

    spec = Gem::Resolver::SpecSpecification.new nil, a1
    def spec.fetch_development_dependencies
      @called = true
    end

    r1 = Gem::Resolver::DependencyRequest.new dep('a', '= 1'), nil

    act = Gem::Resolver::ActivationRequest.new spec, r1, false

    res = Gem::Resolver.new [act]
    res.development = true

    reqs = []

    res.requests spec, act, reqs

    assert_equal ['b (= 2)'], reqs.map { |req| req.to_s }

    assert spec.instance_variable_defined? :@called
  end

  def test_requests_ignore_dependencies
    a1 = util_spec 'a', 1, 'b' => 2

    r1 = Gem::Resolver::DependencyRequest.new dep('a', '= 1'), nil

    act = Gem::Resolver::ActivationRequest.new a1, r1, false

    res = Gem::Resolver.new [a1]
    res.ignore_dependencies = true

    reqs = []

    res.requests a1, act, reqs

    assert_empty reqs
  end

  def test_resolve_conservative
    a1_spec = util_spec 'a', 1
    a2_spec = util_spec 'a', 2 do |s|
      s.add_dependency 'b', 2
      s.add_dependency 'c'
    end
    b1_spec = util_spec 'b', 1
    b2_spec = util_spec 'b', 2
    c1_spec = util_spec 'c', 1 do |s| s.add_dependency 'd', 2 end
    c2_spec = util_spec 'c', 2 do |s| s.add_dependency 'd', 2 end
    d1_spec = util_spec 'd', 1 do |s| s.add_dependency 'e' end
    d2_spec = util_spec 'd', 2 do |s| s.add_dependency 'e' end
    e1_spec = util_spec 'e', 1
    e2_spec = util_spec 'e', 2

    a_dep = make_dep 'a', '= 2'
    e_dep = make_dep 'e'

    # When requesting to install:
    # a-2, e
    deps = [a_dep, e_dep]

    s = set a1_spec, a2_spec, b1_spec, b2_spec, c1_spec, c2_spec, d1_spec, d2_spec, e1_spec, e2_spec

    res = Gem::Resolver.new deps, s

    # With the following gems already installed:
    # a-1, b-1, c-1, e-1
    res.skip_gems = {'a'=>[a1_spec], 'b'=>[b1_spec], 'c'=>[c1_spec], 'e'=>[e1_spec]}

    # Make sure the following gems end up getting used/installed/upgraded:
    # a-2 (upgraded)
    # b-2 (upgraded), specific dependency from a-2
    # c-1 (used, not upgraded), open dependency from a-2
    # d-2 (installed), specific dependency from c-2
    # e-1 (used, not upgraded), open dependency from request
    assert_resolves_to [a2_spec, b2_spec, c1_spec, d2_spec, e1_spec], res
  end

  def test_resolve_development
    a_spec = util_spec 'a', 1 do |s| s.add_development_dependency 'b' end
    b_spec = util_spec 'b', 1 do |s| s.add_development_dependency 'c' end
    c_spec = util_spec 'c', 1

    a_dep = make_dep 'a', '= 1'

    deps = [a_dep]

    s = set a_spec, b_spec, c_spec

    res = Gem::Resolver.new deps, s

    res.development = true

    assert_resolves_to [a_spec, b_spec, c_spec], res
  end

  def test_resolve_development_shallow
    a_spec = util_spec 'a', 1 do |s|
      s.add_development_dependency 'b'
      s.add_runtime_dependency 'd'
    end

    b_spec = util_spec 'b', 1 do |s| s.add_development_dependency 'c' end
    c_spec = util_spec 'c', 1

    d_spec = util_spec 'd', 1 do |s| s.add_development_dependency 'e' end
    e_spec = util_spec 'e', 1

    a_dep = make_dep 'a', '= 1'

    deps = [a_dep]

    s = set a_spec, b_spec, c_spec, d_spec, e_spec

    res = Gem::Resolver.new deps, s

    res.development = true
    res.development_shallow = true

    assert_resolves_to [a_spec, b_spec, d_spec], res
  end

  def test_resolve_remote_missing_dependency
    @fetcher = Gem::FakeFetcher.new
    Gem::RemoteFetcher.fetcher = @fetcher

    a_dep = make_dep 'a', '= 1'

    res = Gem::Resolver.new [a_dep], Gem::Resolver::IndexSet.new

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      res.resolve
    end

    refute_empty e.errors
  end

  def test_no_overlap_specificly
    a = util_spec "a", '1'
    b = util_spec "b", "1"

    ad = make_dep "a", "= 1"
    bd = make_dep "b", "= 1"

    deps = [ad, bd]

    s = set(a, b)

    res = Gem::Resolver.new(deps, s)

    assert_resolves_to [a, b], res
  end

  def test_pulls_in_dependencies
    a = util_spec "a", '1'
    b = util_spec "b", "1", "c" => "= 1"
    c = util_spec "c", "1"

    ad = make_dep "a", "= 1"
    bd = make_dep "b", "= 1"

    deps = [ad, bd]

    s = set(a, b, c)

    res = Gem::Resolver.new(deps, s)

    assert_resolves_to [a, b, c], res
  end

  def test_picks_highest_version
    a1 = util_spec "a", '1'
    a2 = util_spec "a", '2'

    s = set(a1, a2)

    ad = make_dep "a"

    res = Gem::Resolver.new([ad], s)

    assert_resolves_to [a2], res
  end

  def test_picks_best_platform
    is      = Gem::Resolver::IndexSpecification
    unknown = Gem::Platform.new 'unknown'
    a2_p1   = a3_p2 = nil

    spec_fetcher do |fetcher|
              fetcher.spec 'a', 2
      a2_p1 = fetcher.spec 'a', 2 do |s| s.platform = Gem::Platform.local end
      a3_p2 = fetcher.spec 'a', 3 do |s| s.platform = unknown end
    end

    v2 = v(2)
    v3 = v(3)
    source = Gem::Source.new @gem_repo

    s = set

    a2    = is.new s, 'a', v2, source, Gem::Platform::RUBY
    a2_p1 = is.new s, 'a', v2, source, Gem::Platform.local.to_s
    a3_p2 = is.new s, 'a', v3, source, unknown

    s.add a3_p2
    s.add a2_p1
    s.add a2

    ad = make_dep "a"

    res = Gem::Resolver.new([ad], s)

    assert_resolves_to [a2_p1.spec], res
  end

  def test_only_returns_spec_once
    a1 = util_spec "a", "1", "c" => "= 1"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1)

    res = Gem::Resolver.new([ad, bd], s)

    assert_resolves_to [a1, b1, c1], res
  end

  def test_picks_lower_version_when_needed
    a1 = util_spec "a", "1", "c" => ">= 1"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1, c2)

    res = Gem::Resolver.new([ad, bd], s)

    assert_resolves_to [a1, b1, c1], res
  end

  def test_conflict_resolution_only_effects_correct_spec
    a1 = util_spec "a", "1", "c" => ">= 1"
    b1 = util_spec "b", "1", "d" => ">= 1"

    d3 = util_spec "d", "3", "c" => "= 1"
    d4 = util_spec "d", "4", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, d3, d4, c1, c2)

    res = Gem::Resolver.new([ad, bd], s)

    assert_resolves_to [a1, b1, c1, d4], res
  end

  def test_backoff_higher_version_to_satisfy_dep
    t3 = util_spec "railties", "3.2"
    t4 = util_spec "railties", "4.0"

    r3 = util_spec "rails", "3.2", "railties" => "= 3.2"
    r4 = util_spec "rails", "4.0", "railties" => "= 4.0"

    rd = make_dep "rails", "3.2"

    c3 = util_spec "coffee", "3.0", "railties" => "~> 3.0"
    c4 = util_spec "coffee", "4.0", "railties" => "~> 4.0"

    cd = make_dep "coffee"

    s = set(t3, t4, r3, r4, c3, c4)

    res = Gem::Resolver.new([rd, cd], s)

    assert_resolves_to [r3, t3, c3], res
  end

  def test_raises_dependency_error
    a1 = util_spec "a", "1", "c" => "= 1"
    b1 = util_spec "b", "1", "c" => "= 2"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1, c2)

    r = Gem::Resolver.new([ad, bd], s)

    e = assert_raises Gem::DependencyResolutionError do
      r.resolve
    end

    deps = [make_dep("c", "= 2"), make_dep("c", "= 1")]
    assert_equal deps, e.conflicting_dependencies

    con = e.conflict

    act = con.activated
    assert_equal "c-1", act.spec.full_name

    parent = act.parent
    assert_equal "a-1", parent.spec.full_name

    act = con.requester
    assert_equal "b-1", act.spec.full_name
  end

  def test_raises_when_a_gem_is_missing
    ad = make_dep "a"

    r = Gem::Resolver.new([ad], set)

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "Unable to resolve dependency: user requested 'a (>= 0)'",
                 e.message

    assert_equal "a (>= 0)", e.dependency.to_s
  end

  def test_raises_when_a_gem_version_is_missing
    a1 = util_spec "a", "1"

    ad = make_dep "a", "= 3"

    r = Gem::Resolver.new([ad], set(a1))

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "a (= 3)", e.dependency.to_s
  end

  def test_raises_and_reports_a_toplevel_request_properly
    a1 = util_spec "a", "1"
    ad = make_dep "a", "= 3"

    r = Gem::Resolver.new([ad], set(a1))

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "Unable to resolve dependency: user requested 'a (= 3)'",
                 e.message
  end

  def test_raises_and_reports_an_implicit_request_properly
    a1 = util_spec "a", "1" do |s|
      s.add_runtime_dependency 'b', '= 2'
    end

    ad = make_dep "a", "= 1"

    r = Gem::Resolver.new([ad], set(a1))

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_equal "Unable to resolve dependency: 'a (= 1)' requires 'b (= 2)'",
                 e.message
  end

  def test_raises_when_possibles_are_exhausted
    a1 = util_spec "a", "1", "c" => ">= 2"
    b1 = util_spec "b", "1", "c" => "= 1"

    c1 = util_spec "c", "1"
    c2 = util_spec "c", "2"
    c3 = util_spec "c", "3"

    s = set(a1, b1, c1, c2, c3)

    ad = make_dep "a"
    bd = make_dep "b"

    r = Gem::Resolver.new([ad, bd], s)

    e = assert_raises Gem::DependencyResolutionError do
      r.resolve
    end

    dependency = e.conflict.dependency

    assert_includes %w(a b), dependency.name
    assert_equal req('>= 0'), dependency.requirement

    activated = e.conflict.activated
    assert_equal 'c-2', activated.full_name

    assert_equal dep('c', '>= 2'), activated.request.dependency

    assert_equal [dep('c', '= 1'), dep('c', '>= 2')],
                 e.conflict.conflicting_dependencies
  end

  def test_keeps_resolving_after_seeing_satisfied_dep
    a1 = util_spec "a", "1", "b" => "= 1", "c" => "= 1"
    b1 = util_spec "b", "1"
    c1 = util_spec "c", "1"

    ad = make_dep "a"
    bd = make_dep "b"

    s = set(a1, b1, c1)

    r = Gem::Resolver.new([ad, bd], s)

    assert_resolves_to [a1, b1, c1], r
  end

  def test_common_rack_activation_scenario
    rack100 = util_spec "rack", "1.0.0"
    rack101 = util_spec "rack", "1.0.1"

    lib1 =    util_spec "lib", "1", "rack" => ">= 1.0.1"

    rails =   util_spec "rails", "3", "actionpack" => "= 3"
    ap =      util_spec "actionpack", "3", "rack" => ">= 1.0.0"

    d1 = make_dep "rails"
    d2 = make_dep "lib"

    s = set(lib1, rails, ap, rack100, rack101)

    r = Gem::Resolver.new([d1, d2], s)

    assert_resolves_to [rails, ap, rack101, lib1], r

    # check it with the deps reverse too

    r = Gem::Resolver.new([d2, d1], s)

    assert_resolves_to [lib1, rack101, rails, ap], r
  end

  def test_backtracks_to_the_first_conflict
    a1 = util_spec "a", "1"
    a2 = util_spec "a", "2"
    a3 = util_spec "a", "3"
    a4 = util_spec "a", "4"

    d1 = make_dep "a"
    d2 = make_dep "a", ">= 2"
    d3 = make_dep "a", "= 1"

    s = set(a1, a2, a3, a4)

    r = Gem::Resolver.new([d1, d2, d3], s)

    assert_raises Gem::DependencyResolutionError do
      r.resolve
    end
  end

  def test_resolve_conflict
    a1 = util_spec 'a', 1
    a2 = util_spec 'a', 2

    b2 = util_spec 'b', 2, 'a' => '~> 2.0'

    s = set a1, a2, b2

    a_dep = dep 'a', '~> 1.0'
    b_dep = dep 'b'

    r = Gem::Resolver.new [a_dep, b_dep], s

    assert_raises Gem::DependencyResolutionError do
      r.resolve
    end
  end

  def test_resolve_bug_699
    a1 = util_spec 'a', '1', 'b' => '= 2',
                             'c' => '~> 1.0.3'

    b1 = util_spec 'b', '2', 'c' => '~> 1.0'

    c1 = util_spec 'c', '1.0.9'
    c2 = util_spec 'c', '1.1.0'
    c3 = util_spec 'c', '1.2.0'

    s = set a1, b1, c1, c2, c3

    a_dep = dep 'a', '= 1'

    r = Gem::Resolver.new [a_dep], s

    assert_resolves_to [a1, b1, c1], r
  end

  def test_resolve_rollback
    a1 = util_spec 'a', 1
    a2 = util_spec 'a', 2

    b1 = util_spec 'b', 1, 'a' => '~> 1.0'
    b2 = util_spec 'b', 2, 'a' => '~> 2.0'

    s = set a1, a2, b1, b2

    a_dep = dep 'a', '~> 1.0'
    b_dep = dep 'b'

    r = Gem::Resolver.new [a_dep, b_dep], s

    assert_resolves_to [a1, b1], r
  end

  # actionmailer 2.3.4
  # activemerchant 1.5.0
  # activesupport 2.3.5, 2.3.4
  # Activemerchant needs activesupport >= 2.3.2. When you require activemerchant, it will activate the latest version that meets that requirement which is 2.3.5. Actionmailer on the other hand needs activesupport = 2.3.4. When rubygems tries to activate activesupport 2.3.4, it will raise an error.


  def test_simple_activesupport_problem
    sup1  = util_spec "activesupport", "2.3.4"
    sup2  = util_spec "activesupport", "2.3.5"

    merch = util_spec "activemerchant", "1.5.0", "activesupport" => ">= 2.3.2"
    mail =  util_spec "actionmailer", "2.3.4", "activesupport" => "= 2.3.4"

    s = set(mail, merch, sup1, sup2)

    d1 = make_dep "activemerchant"
    d2 = make_dep "actionmailer"

    r = Gem::Resolver.new([d1, d2], s)

    assert_resolves_to [merch, mail, sup1], r
  end

  def test_second_level_backout
    b1 = new_spec "b", "1", { "c" => ">= 1" }, "lib/b.rb"
    b2 = new_spec "b", "2", { "c" => ">= 2" }, "lib/b.rb"
    c1 = new_spec "c", "1"
    c2 = new_spec "c", "2"
    d1 = new_spec "d", "1", { "c" => "< 2" },  "lib/d.rb"
    d2 = new_spec "d", "2", { "c" => "< 2" },  "lib/d.rb"

    s = set(b1, b2, c1, c2, d1, d2)

    p1 = make_dep "b", "> 0"
    p2 = make_dep "d", "> 0"

    r = Gem::Resolver.new([p1, p2], s)

    assert_resolves_to [b1, c1, d2], r
  end

  def test_sorts_by_source_then_version
    sourceA = Gem::Source.new 'http://example.com/a'
    sourceB = Gem::Source.new 'http://example.com/b'
    sourceC = Gem::Source.new 'http://example.com/c'

    spec_A_1 = new_spec 'some-dep', '0.0.1'
    spec_A_2 = new_spec 'some-dep', '1.0.0'
    spec_B_1 = new_spec 'some-dep', '0.0.1'
    spec_B_2 = new_spec 'some-dep', '0.0.2'
    spec_C_1 = new_spec 'some-dep', '0.1.0'

    set = StaticSet.new [
      Gem::Resolver::SpecSpecification.new(nil, spec_B_1, sourceB),
      Gem::Resolver::SpecSpecification.new(nil, spec_B_2, sourceB),
      Gem::Resolver::SpecSpecification.new(nil, spec_C_1, sourceC),
      Gem::Resolver::SpecSpecification.new(nil, spec_A_2, sourceA),
      Gem::Resolver::SpecSpecification.new(nil, spec_A_1, sourceA),
    ]

    dependency = make_dep 'some-dep', '> 0'

    resolver = Gem::Resolver.new [dependency], set

    assert_resolves_to [spec_B_2], resolver
  end

  def test_select_local_platforms
    r = Gem::Resolver.new nil, nil

    a1    = util_spec 'a', 1
    a1_p1 = util_spec 'a', 1 do |s| s.platform = Gem::Platform.local end
    a1_p2 = util_spec 'a', 1 do |s| s.platform = 'unknown'           end

    selected = r.select_local_platforms [a1, a1_p1, a1_p2]

    assert_equal [a1, a1_p1], selected
  end

  def test_search_for_local_platform_partial_string_match
    a1    = util_spec 'a', 1
    a1_p1 = util_spec 'a', 1 do |s| s.platform = Gem::Platform.local.os end
    a1_p2 = util_spec 'a', 1 do |s| s.platform = 'unknown'              end

    s = set(a1_p1, a1_p2, a1)
    d = [make_dep('a')]
    r = Gem::Resolver.new(d, s)

    assert_resolves_to [a1_p1], r
  end

  def test_raises_and_explains_when_platform_prevents_install
    a1 = util_spec "a", "1" do |s|
      s.platform = Gem::Platform.new %w[c p 1]
    end

    ad = make_dep "a", "= 1"

    r = Gem::Resolver.new([ad], set(a1))

    e = assert_raises Gem::UnsatisfiableDepedencyError do
      r.resolve
    end

    assert_match "No match for 'a (= 1)' on this platform. Found: c-p-1",
                 e.message
  end

end