summaryrefslogtreecommitdiff
path: root/lib/spack/spack/test/conftest.py
blob: 419cbec196cc767fb7989bbc4d62b74cd0252731 (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
##############################################################################
# Copyright (c) 2013-2018, Lawrence Livermore National Security, LLC.
# Produced at the Lawrence Livermore National Laboratory.
#
# This file is part of Spack.
# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
# LLNL-CODE-647188
#
# For details, see https://github.com/spack/spack
# Please also see the NOTICE and LICENSE files for our notice and the LGPL.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License (as
# published by the Free Software Foundation) version 2.1, February 1999.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
# conditions of the GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##############################################################################
import collections
import copy
import inspect
import os
import os.path
import shutil
import re

import ordereddict_backport
import py
import pytest
import ruamel.yaml as yaml

from llnl.util.filesystem import remove_linked_tree

import spack.architecture
import spack.config
import spack.caches
import spack.database
import spack.directory_layout
import spack.paths
import spack.platforms.test
import spack.repo
import spack.stage
import spack.util.executable
from spack.util.pattern import Bunch
from spack.dependency import Dependency
from spack.package import PackageBase
from spack.fetch_strategy import FetchStrategyComposite, URLFetchStrategy
from spack.fetch_strategy import FetchError
from spack.spec import Spec
from spack.version import Version


# Hooks to add command line options or set other custom behaviors.
# They must be placed here to be found by pytest. See:
#
# https://docs.pytest.org/en/latest/writing_plugins.html
#
def pytest_addoption(parser):
    group = parser.getgroup("Spack specific command line options")
    group.addoption(
        '--fast', action='store_true', default=False,
        help='runs only "fast" unit tests, instead of the whole suite')


def pytest_collection_modifyitems(config, items):
    if not config.getoption('--fast'):
        # --fast not given, run all the tests
        return

    slow_tests = ['db', 'network', 'maybeslow']
    skip_as_slow = pytest.mark.skip(
        reason='skipped slow test [--fast command line option given]'
    )
    for item in items:
        if any(x in item.keywords for x in slow_tests):
            item.add_marker(skip_as_slow)


#
# These fixtures are applied to all tests
#
@pytest.fixture(scope='function', autouse=True)
def no_chdir():
    """Ensure that no test changes Spack's working dirctory.

    This prevents Spack tests (and therefore Spack commands) from
    changing the working directory and causing other tests to fail
    mysteriously. Tests should use ``working_dir`` or ``py.path``'s
    ``.as_cwd()`` instead of ``os.chdir`` to avoid failing this check.

    We assert that the working directory hasn't changed, unless the
    original wd somehow ceased to exist.

    """
    original_wd = os.getcwd()
    yield
    if os.path.isdir(original_wd):
        assert os.getcwd() == original_wd


@pytest.fixture(scope='session', autouse=True)
def mock_stage(tmpdir_factory):
    """Mocks up a fake stage directory for use by tests."""
    stage_path = spack.paths.stage_path
    new_stage = str(tmpdir_factory.mktemp('mock_stage'))
    spack.paths.stage_path = new_stage
    yield new_stage
    spack.paths.stage_path = stage_path


@pytest.fixture(scope='session')
def _ignore_stage_files():
    """Session-scoped helper for check_for_leftover_stage_files.

    Used to track which leftover files in the stage have been seen.
    """
    # to start with, ignore the .lock file at the stage root.
    return set(['.lock'])


def remove_whatever_it_is(path):
    """Type-agnostic remove."""
    if os.path.isfile(path):
        os.remove(path)
    elif os.path.islink(path):
        remove_linked_tree(path)
    else:
        shutil.rmtree(path)


@pytest.fixture(scope='function', autouse=True)
def check_for_leftover_stage_files(request, mock_stage, _ignore_stage_files):
    """Ensure that each test leaves a clean stage when done.

    This can be disabled for tests that are expected to dirty the stage
    by adding::

        @pytest.mark.disable_clean_stage_check

    to tests that need it.
    """
    yield

    files_in_stage = set()
    if os.path.exists(spack.paths.stage_path):
        files_in_stage = set(
            os.listdir(spack.paths.stage_path)) - _ignore_stage_files

    if 'disable_clean_stage_check' in request.keywords:
        # clean up after tests that are expected to be dirty
        for f in files_in_stage:
            path = os.path.join(spack.paths.stage_path, f)
            remove_whatever_it_is(path)
    else:
        _ignore_stage_files |= files_in_stage
        assert not files_in_stage


@pytest.fixture(autouse=True)
def mock_fetch_cache(monkeypatch):
    """Substitutes spack.paths.fetch_cache with a mock object that does nothing
    and raises on fetch.
    """
    class MockCache(object):
        def store(self, copy_cmd, relative_dest):
            pass

        def fetcher(self, target_path, digest, **kwargs):
            return MockCacheFetcher()

    class MockCacheFetcher(object):
        def set_stage(self, stage):
            pass

        def fetch(self):
            raise FetchError('Mock cache always fails for tests')

        def __str__(self):
            return "[mock fetch cache]"

    monkeypatch.setattr(spack.caches, 'fetch_cache', MockCache())


# FIXME: The lines below should better be added to a fixture with
# FIXME: session-scope. Anyhow doing it is not easy, as it seems
# FIXME: there's some weird interaction with compilers during concretization.
spack.architecture.real_platform = spack.architecture.platform
spack.architecture.platform = lambda: spack.platforms.test.Test()

##########
# Test-specific fixtures
##########


@pytest.fixture(scope='session')
def repo_path():
    """Session scoped RepoPath object pointing to the mock repository"""
    return spack.repo.RepoPath(spack.paths.mock_packages_path)


@pytest.fixture(scope='module')
def mock_packages(repo_path):
    """Use the 'builtin.mock' repository instead of 'builtin'"""
    mock_repo = copy.deepcopy(repo_path)
    with spack.repo.swap(mock_repo):
        yield


@pytest.fixture(scope='function')
def mutable_mock_packages(mock_packages, repo_path):
    """Function-scoped mock packages, for tests that need to modify them."""
    mock_repo = copy.deepcopy(repo_path)
    with spack.repo.swap(mock_repo):
        yield


@pytest.fixture(scope='session')
def linux_os():
    """Returns a named tuple with attributes 'name' and 'version'
    representing the OS.
    """
    platform = spack.architecture.platform()
    name, version = 'debian', '6'
    if platform.name == 'linux':
        platform = spack.architecture.platform()
        current_os = platform.operating_system('default_os')
        name, version = current_os.name, current_os.version
    LinuxOS = collections.namedtuple('LinuxOS', ['name', 'version'])
    return LinuxOS(name=name, version=version)


@pytest.fixture(scope='session')
def configuration_dir(tmpdir_factory, linux_os):
    """Copies mock configuration files in a temporary directory. Returns the
    directory path.
    """
    tmpdir = tmpdir_factory.mktemp('configurations')

    # Name of the yaml files in the test/data folder
    test_path = py.path.local(spack.paths.test_path)
    compilers_yaml = test_path.join('data', 'compilers.yaml')
    packages_yaml = test_path.join('data', 'packages.yaml')
    config_yaml = test_path.join('data', 'config.yaml')
    repos_yaml = test_path.join('data', 'repos.yaml')

    # Create temporary 'site' and 'user' folders
    tmpdir.ensure('site', dir=True)
    tmpdir.ensure('user', dir=True)

    # Copy the configurations that don't need further work
    packages_yaml.copy(tmpdir.join('site', 'packages.yaml'))
    config_yaml.copy(tmpdir.join('site', 'config.yaml'))
    repos_yaml.copy(tmpdir.join('site', 'repos.yaml'))

    # Write the one that needs modifications
    content = ''.join(compilers_yaml.read()).format(linux_os)
    t = tmpdir.join('site', 'compilers.yaml')
    t.write(content)
    return tmpdir


@pytest.fixture(scope='module')
def config(configuration_dir):
    """Hooks the mock configuration files into spack.config"""
    # Set up a mock config scope
    spack.package_prefs.PackagePrefs.clear_caches()

    real_configuration = spack.config.config

    spack.config.config = spack.config.Configuration(
        *[spack.config.ConfigScope(name, str(configuration_dir.join(name)))
          for name in ['site', 'system', 'user']])

    yield spack.config.config

    spack.config.config = real_configuration
    spack.package_prefs.PackagePrefs.clear_caches()


@pytest.fixture(scope='function')
def mutable_config(tmpdir_factory, configuration_dir, config):
    """Like config, but tests can modify the configuration."""
    spack.package_prefs.PackagePrefs.clear_caches()

    mutable_dir = tmpdir_factory.mktemp('mutable_config').join('tmp')
    configuration_dir.copy(mutable_dir)

    real_configuration = spack.config.config

    spack.config.config = spack.config.Configuration(
        *[spack.config.ConfigScope(name, str(mutable_dir))
          for name in ['site', 'system', 'user']])

    yield spack.config.config

    spack.config.config = real_configuration
    spack.package_prefs.PackagePrefs.clear_caches()


def _populate(mock_db):
    """Populate a mock database with packages.

    Here is what the mock DB looks like:

    o  mpileaks     o  mpileaks'    o  mpileaks''
    |\              |\              |\
    | o  callpath   | o  callpath'  | o  callpath''
    |/|             |/|             |/|
    o |  mpich      o |  mpich2     o |  zmpi
      |               |             o |  fake
      |               |               |
      |               |______________/
      | .____________/
      |/
      o  dyninst
      |\
      | o  libdwarf
      |/
      o  libelf
    """
    def _install(spec):
        s = spack.spec.Spec(spec).concretized()
        pkg = spack.repo.get(s)
        pkg.do_install(fake=True, explicit=True)

    # Transaction used to avoid repeated writes.
    with mock_db.write_transaction():
        _install('mpileaks ^mpich')
        _install('mpileaks ^mpich2')
        _install('mpileaks ^zmpi')
        _install('externaltest')


@pytest.fixture(scope='module')
def database(tmpdir_factory, mock_packages, config):
    """Creates a mock database with some packages installed note that
    the ref count for dyninst here will be 3, as it's recycled
    across each install.
    """
    # save the real store
    real_store = spack.store.store

    # Make a fake install directory
    install_path = tmpdir_factory.mktemp('install_for_database')

    # Make fake store (database and install layout)
    tmp_store = spack.store.Store(str(install_path))
    spack.store.store = tmp_store

    _populate(tmp_store.db)

    yield tmp_store.db

    with tmp_store.db.write_transaction():
        for spec in tmp_store.db.query():
            if spec.package.installed:
                PackageBase.uninstall_by_spec(spec, force=True)
            else:
                tmp_store.db.remove(spec)

    install_path.remove(rec=1)
    spack.store.store = real_store


@pytest.fixture(scope='function')
def mutable_database(database):
    """For tests that need to modify the database instance."""
    yield database
    with database.write_transaction():
        for spec in spack.store.db.query():
            PackageBase.uninstall_by_spec(spec, force=True)
    _populate(database)


@pytest.fixture(scope='function')
def install_mockery(tmpdir, config, mock_packages):
    """Hooks a fake install directory, DB, and stage directory into Spack."""
    real_store = spack.store.store
    spack.store.store = spack.store.Store(str(tmpdir.join('opt')))

    # We use a fake package, so temporarily disable checksumming
    with spack.config.override('config:checksum', False):
        yield

    tmpdir.join('opt').remove()
    spack.store.store = real_store


@pytest.fixture()
def mock_fetch(mock_archive):
    """Fake the URL for a package so it downloads from a file."""
    fetcher = FetchStrategyComposite()
    fetcher.append(URLFetchStrategy(mock_archive.url))

    @property
    def fake_fn(self):
        return fetcher

    orig_fn = PackageBase.fetcher
    PackageBase.fetcher = fake_fn
    yield
    PackageBase.fetcher = orig_fn


@pytest.fixture()
def module_configuration(monkeypatch, request):
    """Reads the module configuration file from the mock ones prepared
    for tests and monkeypatches the right classes to hook it in.
    """
    # Class of the module file writer
    writer_cls = getattr(request.module, 'writer_cls')
    # Module where the module file writer is defined
    writer_mod = inspect.getmodule(writer_cls)
    # Key for specific settings relative to this module type
    writer_key = str(writer_mod.__name__).split('.')[-1]
    # Root folder for configuration
    root_for_conf = os.path.join(
        spack.paths.test_path, 'data', 'modules', writer_key
    )

    def _impl(filename):

        file = os.path.join(root_for_conf, filename + '.yaml')
        with open(file) as f:
            configuration = yaml.load(f)

        monkeypatch.setattr(
            spack.modules.common,
            'configuration',
            configuration
        )
        monkeypatch.setattr(
            writer_mod,
            'configuration',
            configuration[writer_key]
        )
        monkeypatch.setattr(
            writer_mod,
            'configuration_registry',
            {}
        )
    return _impl

##########
# Fake archives and repositories
##########


@pytest.fixture(scope='session')
def mock_archive(tmpdir_factory):
    """Creates a very simple archive directory with a configure script and a
    makefile that installs to a prefix. Tars it up into an archive.
    """
    tar = spack.util.executable.which('tar', required=True)

    tmpdir = tmpdir_factory.mktemp('mock-archive-dir')
    repo_name = 'mock-archive-repo'
    tmpdir.ensure(repo_name, dir=True)
    repodir = tmpdir.join(repo_name)

    # Create the configure script
    configure_path = str(tmpdir.join(repo_name, 'configure'))
    with open(configure_path, 'w') as f:
        f.write(
            "#!/bin/sh\n"
            "prefix=$(echo $1 | sed 's/--prefix=//')\n"
            "cat > Makefile <<EOF\n"
            "all:\n"
            "\techo Building...\n\n"
            "install:\n"
            "\tmkdir -p $prefix\n"
            "\ttouch $prefix/dummy_file\n"
            "EOF\n"
        )
    os.chmod(configure_path, 0o755)

    # Archive it
    with tmpdir.as_cwd():
        archive_name = '{0}.tar.gz'.format(repo_name)
        tar('-czf', archive_name, repo_name)

    Archive = collections.namedtuple('Archive',
                                     ['url', 'path', 'archive_file'])
    archive_file = str(tmpdir.join(archive_name))

    # Return the url
    yield Archive(
        url=('file://' + archive_file),
        archive_file=archive_file,
        path=str(repodir))


@pytest.fixture(scope='session')
def mock_git_repository(tmpdir_factory):
    """Creates a very simple git repository with two branches and
    two commits.
    """
    git = spack.util.executable.which('git', required=True)

    tmpdir = tmpdir_factory.mktemp('mock-git-repo-dir')
    repo_name = 'mock-git-repo'
    tmpdir.ensure(repo_name, dir=True)
    repodir = tmpdir.join(repo_name)

    # Initialize the repository
    with repodir.as_cwd():
        git('init')
        git('config', 'user.name', 'Spack')
        git('config', 'user.email', 'spack@spack.io')
        url = 'file://' + str(repodir)

        # r0 is just the first commit
        r0_file = 'r0_file'
        repodir.ensure(r0_file)
        git('add', r0_file)
        git('commit', '-m', 'mock-git-repo r0')

        branch = 'test-branch'
        branch_file = 'branch_file'
        git('branch', branch)

        tag_branch = 'tag-branch'
        tag_file = 'tag_file'
        git('branch', tag_branch)

        # Check out first branch
        git('checkout', branch)
        repodir.ensure(branch_file)
        git('add', branch_file)
        git('commit', '-m' 'r1 test branch')

        # Check out a second branch and tag it
        git('checkout', tag_branch)
        repodir.ensure(tag_file)
        git('add', tag_file)
        git('commit', '-m' 'tag test branch')

        tag = 'test-tag'
        git('tag', tag)

        git('checkout', 'master')

        # R1 test is the same as test for branch
        rev_hash = lambda x: git('rev-parse', x, output=str).strip()
        r1 = rev_hash(branch)
        r1_file = branch_file

    checks = {
        'master': Bunch(
            revision='master', file=r0_file, args={'git': str(repodir)}
        ),
        'branch': Bunch(
            revision=branch, file=branch_file, args={
                'git': str(repodir), 'branch': branch
            }
        ),
        'tag': Bunch(
            revision=tag, file=tag_file, args={'git': str(repodir), 'tag': tag}
        ),
        'commit': Bunch(
            revision=r1, file=r1_file, args={'git': str(repodir), 'commit': r1}
        )
    }

    t = Bunch(checks=checks, url=url, hash=rev_hash, path=str(repodir))
    yield t


@pytest.fixture(scope='session')
def mock_hg_repository(tmpdir_factory):
    """Creates a very simple hg repository with two commits."""
    hg = spack.util.executable.which('hg', required=True)

    tmpdir = tmpdir_factory.mktemp('mock-hg-repo-dir')
    repo_name = 'mock-hg-repo'
    tmpdir.ensure(repo_name, dir=True)
    repodir = tmpdir.join(repo_name)

    get_rev = lambda: hg('id', '-i', output=str).strip()

    # Initialize the repository
    with repodir.as_cwd():
        url = 'file://' + str(repodir)
        hg('init')

        # Commit file r0
        r0_file = 'r0_file'
        repodir.ensure(r0_file)
        hg('add', r0_file)
        hg('commit', '-m', 'revision 0', '-u', 'test')
        r0 = get_rev()

        # Commit file r1
        r1_file = 'r1_file'
        repodir.ensure(r1_file)
        hg('add', r1_file)
        hg('commit', '-m' 'revision 1', '-u', 'test')
        r1 = get_rev()

    checks = {
        'default': Bunch(
            revision=r1, file=r1_file, args={'hg': str(repodir)}
        ),
        'rev0': Bunch(
            revision=r0, file=r0_file, args={
                'hg': str(repodir), 'revision': r0
            }
        )
    }
    t = Bunch(checks=checks, url=url, hash=get_rev, path=str(repodir))
    yield t


@pytest.fixture(scope='session')
def mock_svn_repository(tmpdir_factory):
    """Creates a very simple svn repository with two commits."""
    svn = spack.util.executable.which('svn', required=True)
    svnadmin = spack.util.executable.which('svnadmin', required=True)

    tmpdir = tmpdir_factory.mktemp('mock-svn-stage')
    repo_name = 'mock-svn-repo'
    tmpdir.ensure(repo_name, dir=True)
    repodir = tmpdir.join(repo_name)
    url = 'file://' + str(repodir)

    # Initialize the repository
    with repodir.as_cwd():
        # NOTE: Adding --pre-1.5-compatible works for NERSC
        # Unknown if this is also an issue at other sites.
        svnadmin('create', '--pre-1.5-compatible', str(repodir))

        # Import a structure (first commit)
        r0_file = 'r0_file'
        tmpdir.ensure('tmp-path', r0_file)
        tmp_path = tmpdir.join('tmp-path')
        svn('import',
            str(tmp_path),
            url,
            '-m',
            'Initial import r0')
        tmp_path.remove()

        # Second commit
        r1_file = 'r1_file'
        svn('checkout', url, str(tmp_path))
        tmpdir.ensure('tmp-path', r1_file)

        with tmp_path.as_cwd():
            svn('add', str(tmpdir.ensure('tmp-path', r1_file)))
            svn('ci', '-m', 'second revision r1')

        tmp_path.remove()
        r0 = '1'
        r1 = '2'

    checks = {
        'default': Bunch(
            revision=r1, file=r1_file, args={'svn': url}),
        'rev0': Bunch(
            revision=r0, file=r0_file, args={
                'svn': url, 'revision': r0})
    }

    def get_rev():
        output = svn('info', output=str)
        assert "Revision" in output
        for line in output.split('\n'):
            match = re.match(r'Revision: (\d+)', line)
            if match:
                return match.group(1)

    t = Bunch(checks=checks, url=url, hash=get_rev, path=str(repodir))
    yield t


##########
# Mock packages
##########


class MockPackage(object):
    def __init__(self, name, dependencies, dependency_types, conditions=None,
                 versions=None):
        self.name = name
        self.spec = None
        self.dependencies = ordereddict_backport.OrderedDict()

        assert len(dependencies) == len(dependency_types)
        for dep, dtype in zip(dependencies, dependency_types):
            d = Dependency(self, Spec(dep.name), type=dtype)
            if not conditions or dep.name not in conditions:
                self.dependencies[dep.name] = {Spec(name): d}
            else:
                dep_conditions = conditions[dep.name]
                dep_conditions = dict(
                    (Spec(x), Dependency(self, Spec(y), type=dtype))
                    for x, y in dep_conditions.items())
                self.dependencies[dep.name] = dep_conditions

        if versions:
            self.versions = versions
        else:
            versions = list(Version(x) for x in [1, 2, 3])
            self.versions = dict((x, {'preferred': False}) for x in versions)

        self.variants = {}
        self.provided = {}
        self.conflicts = {}
        self.patches = {}


class MockPackageMultiRepo(object):
    def __init__(self, packages):
        self.spec_to_pkg = dict((x.name, x) for x in packages)
        self.spec_to_pkg.update(
            dict(('mockrepo.' + x.name, x) for x in packages))

    def get(self, spec):
        if not isinstance(spec, spack.spec.Spec):
            spec = Spec(spec)
        return self.spec_to_pkg[spec.name]

    def get_pkg_class(self, name):
        return self.spec_to_pkg[name]

    def exists(self, name):
        return name in self.spec_to_pkg

    def is_virtual(self, name):
        return False

    def repo_for_pkg(self, name):
        import collections
        Repo = collections.namedtuple('Repo', ['namespace'])
        return Repo('mockrepo')

##########
# Specs of various kind
##########


@pytest.fixture(
    params=[
        'conflict%clang',
        'conflict%clang+foo',
        'conflict-parent%clang',
        'conflict-parent@0.9^conflict~foo'
    ]
)
def conflict_spec(request):
    """Specs which violate constraints specified with the "conflicts"
    directive in the "conflict" package.
    """
    return request.param


@pytest.fixture(
    params=[
        'conflict%~'
    ]
)
def invalid_spec(request):
    """Specs that do not parse cleanly due to invalid formatting.
    """
    return request.param