Esempio n. 1
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def test_lock_checks_group(tmpdir):
    """Ensure lock checks work with a self-owned, non-self-group repo."""
    uid = getuid()
    gid = next((g for g in group_ids() if g != uid), None)
    if not gid:
        pytest.skip("user has no group with gid != uid")

    # self-owned, another group
    tmpdir.chown(uid, gid)

    # safe
    path = str(tmpdir)
    tmpdir.chmod(0o744)
    lk.check_lock_safety(path)

    # unsafe
    tmpdir.chmod(0o774)
    with pytest.raises(spack.error.SpackError):
        lk.check_lock_safety(path)

    # unsafe
    tmpdir.chmod(0o777)
    with pytest.raises(spack.error.SpackError):
        lk.check_lock_safety(path)

    # safe
    tmpdir.chmod(0o474)
    lk.check_lock_safety(path)

    # safe
    tmpdir.chmod(0o477)
    lk.check_lock_safety(path)
Esempio n. 2
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def test_lock_checks_user(tmpdir):
    """Ensure lock checks work with a self-owned, self-group repo."""
    uid = getuid()
    if uid not in group_ids():
        pytest.skip("user has no group with gid == uid")

    # self-owned, own group
    tmpdir.chown(uid, uid)

    # safe
    path = str(tmpdir)
    tmpdir.chmod(0o744)
    lk.check_lock_safety(path)

    # safe
    tmpdir.chmod(0o774)
    lk.check_lock_safety(path)

    # unsafe
    tmpdir.chmod(0o777)
    with pytest.raises(spack.error.SpackError):
        lk.check_lock_safety(path)

    # safe
    tmpdir.chmod(0o474)
    lk.check_lock_safety(path)

    # safe
    tmpdir.chmod(0o477)
    lk.check_lock_safety(path)
Esempio n. 3
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def check_stage_dir_perms(prefix, path):
    """Check the stage directory perms to ensure match expectations."""
    # Ensure the path's subdirectories -- to `$user` -- have their parent's
    # perms while those from `$user` on are owned and restricted to the
    # user.
    assert path.startswith(prefix)

    user = getpass.getuser()
    prefix_status = os.stat(prefix)
    uid = getuid()

    # Obtain lists of ancestor and descendant paths of the $user node, if any.
    #
    # Skip processing prefix ancestors since no guarantee they will be in the
    # required group (e.g. $TEMPDIR on HPC machines).
    skip = prefix if prefix.endswith(os.sep) else prefix + os.sep
    group_paths, user_node, user_paths = partition_path(
        path.replace(skip, ""), user)

    for p in group_paths:
        p_status = os.stat(os.path.join(prefix, p))
        assert p_status.st_gid == prefix_status.st_gid
        assert p_status.st_mode == prefix_status.st_mode

    # Add the path ending with the $user node to the user paths to ensure paths
    # from $user (on down) meet the ownership and permission requirements.
    if user_node:
        user_paths.insert(0, user_node)

    for p in user_paths:
        p_status = os.stat(os.path.join(prefix, p))
        assert uid == p_status.st_uid
        assert p_status.st_mode & stat.S_IRWXU == stat.S_IRWXU
Esempio n. 4
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def create_stage_root(path):
    # type: (str) -> None
    """Create the stage root directory and ensure appropriate access perms."""
    assert os.path.isabs(path) and len(path.strip()) > 1

    err_msg = 'Cannot create stage root {0}: Access to {1} is denied'

    user_uid = getuid()

    # Obtain lists of ancestor and descendant paths of the $user node, if any.
    group_paths, user_node, user_paths = partition_path(
        path, getpass.getuser())

    for p in group_paths:
        if not os.path.exists(p):
            # Ensure access controls of subdirs created above `$user` inherit
            # from the parent and share the group.
            par_stat = os.stat(os.path.dirname(p))
            mkdirp(p, group=par_stat.st_gid, mode=par_stat.st_mode)

            p_stat = os.stat(p)
            if par_stat.st_gid != p_stat.st_gid:
                tty.warn(
                    "Expected {0} to have group {1}, but it is {2}".format(
                        p, par_stat.st_gid, p_stat.st_gid))

            if par_stat.st_mode & p_stat.st_mode != par_stat.st_mode:
                tty.warn(
                    "Expected {0} to support mode {1}, but it is {2}".format(
                        p, par_stat.st_mode, p_stat.st_mode))

            if not can_access(p):
                raise OSError(errno.EACCES, err_msg.format(path, p))

    # Add the path ending with the $user node to the user paths to ensure paths
    # from $user (on down) meet the ownership and permission requirements.
    if user_node:
        user_paths.insert(0, user_node)

    for p in user_paths:
        # Ensure access controls of subdirs from `$user` on down are
        # restricted to the user.
        owner_uid = get_owner_uid(p)
        if user_uid != owner_uid:
            tty.warn(
                "Expected user {0} to own {1}, but it is owned by {2}".format(
                    user_uid, p, owner_uid))

    spack_src_subdir = os.path.join(path, _source_path_subdir)
    # When staging into a user-specified directory with `spack stage -p <PATH>`, we need
    # to ensure the `spack-src` subdirectory exists, as we can't rely on it being
    # created automatically by spack. It's not clear why this is the case for `spack
    # stage -p`, but since `mkdirp()` is idempotent, this should not change the behavior
    # for any other code paths.
    if not os.path.isdir(spack_src_subdir):
        mkdirp(spack_src_subdir, mode=stat.S_IRWXU)
Esempio n. 5
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    def test_create_stage_root_bad_uid(self, tmpdir, monkeypatch):
        """
        Test the code path that uses an existing user path -- whether `$user`
        in `$tempdir` or not -- and triggers the generation of the UID
        mismatch warning.

        This situation can happen with some `config:build_stage` settings
        for teams using a common service account for installing software.
        """
        orig_stat = os.stat

        class MinStat:
            st_mode = -1
            st_uid = -1

        def _stat(path):
            p_stat = orig_stat(path)

            fake_stat = MinStat()
            fake_stat.st_mode = p_stat.st_mode
            return fake_stat

        user_dir = tmpdir.join(getpass.getuser())
        user_dir.ensure(dir=True)
        user_path = str(user_dir)

        # TODO: If we could guarantee access to the monkeypatch context
        # function (i.e., 3.6.0 on), the call and assertion could be moved
        # to a with block, such as:
        #
        #  with monkeypatch.context() as m:
        #      m.setattr(os, 'stat', _stat)
        #      spack.stage.create_stage_root(user_path)
        #      assert os.stat(user_path).st_uid != os.getuid()
        monkeypatch.setattr(os, 'stat', _stat)
        spack.stage.create_stage_root(user_path)

        # The following check depends on the patched os.stat as a poor
        # substitute for confirming the generated warnings.
        assert os.stat(user_path).st_uid != getuid()
Esempio n. 6
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def test_write_lock_timeout_with_multiple_readers_3_1_ranges(lock_path):
    multiproc_test(AcquireRead(lock_path, 0, 5), AcquireRead(lock_path, 5, 5),
                   AcquireRead(lock_path, 10, 5),
                   TimeoutWrite(lock_path, 0, 15))


def test_write_lock_timeout_with_multiple_readers_3_2_ranges(lock_path):
    multiproc_test(AcquireRead(lock_path, 0, 5), AcquireRead(lock_path, 5, 5),
                   AcquireRead(lock_path, 10,
                               5), TimeoutWrite(lock_path, 3, 10),
                   TimeoutWrite(lock_path, 5, 1))


@pytest.mark.skipif(getuid() == 0, reason='user is root')
def test_read_lock_on_read_only_lockfile(lock_dir, lock_path):
    """read-only directory, read-only lockfile."""
    touch(lock_path)
    with read_only(lock_path, lock_dir):
        lock = lk.Lock(lock_path)

        with lk.ReadTransaction(lock):
            pass

        with pytest.raises(lk.LockROFileError):
            with lk.WriteTransaction(lock):
                pass


def test_read_lock_read_only_dir_writable_lockfile(lock_dir, lock_path):
Esempio n. 7
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                                                  mutable_mock_repo,
                                                  _platform_executables,
                                                  tmpdir, monkeypatch):
    """The user runs 'spack external find'; the default path for storing
    manifest files exists but is empty. Ensure that the command does not
    fail.
    """
    empty_manifest_dir = str(tmpdir.mkdir('manifest_dir'))
    monkeypatch.setenv('PATH', '')
    monkeypatch.setattr(spack.cray_manifest, 'default_path',
                        empty_manifest_dir)
    external('find')


@pytest.mark.skipif(sys.platform == 'win32', reason="Can't chmod on Windows")
@pytest.mark.skipif(getuid() == 0, reason='user is root')
def test_find_external_manifest_with_bad_permissions(
        mutable_config, working_env, mock_executable, mutable_mock_repo,
        _platform_executables, tmpdir, monkeypatch):
    """The user runs 'spack external find'; the default path for storing
    manifest files exists but with insufficient permissions. Check that
    the command does not fail.
    """
    test_manifest_dir = str(tmpdir.mkdir('manifest_dir'))
    test_manifest_file_path = os.path.join(test_manifest_dir, 'badperms.json')
    touch(test_manifest_file_path)
    monkeypatch.setenv('PATH', '')
    monkeypatch.setattr(spack.cray_manifest, 'default_path', test_manifest_dir)
    try:
        os.chmod(test_manifest_file_path, 0)
        output = external('find')
Esempio n. 8
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class TestStage(object):

    stage_name = 'spack-test-stage'

    def test_setup_and_destroy_name_with_tmp(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url, name=self.stage_name) as stage:
            check_setup(stage, self.stage_name, archive)
        check_destroy(stage, self.stage_name)

    def test_setup_and_destroy_name_without_tmp(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url, name=self.stage_name) as stage:
            check_setup(stage, self.stage_name, archive)
        check_destroy(stage, self.stage_name)

    def test_setup_and_destroy_no_name_with_tmp(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url) as stage:
            check_setup(stage, None, archive)
        check_destroy(stage, None)

    def test_noexpand_stage_file(self, mock_stage_archive,
                                 mock_noexpand_resource):
        """When creating a stage with a nonexpanding URL, the 'archive_file'
        property of the stage should refer to the path of that file.
        """
        test_noexpand_fetcher = spack.fetch_strategy.from_kwargs(
            url=_file_prefix + mock_noexpand_resource, expand=False)
        with Stage(test_noexpand_fetcher) as stage:
            stage.fetch()
            stage.expand_archive()
            assert os.path.exists(stage.archive_file)

    @pytest.mark.disable_clean_stage_check
    def test_composite_stage_with_noexpand_resource(self, mock_stage_archive,
                                                    mock_noexpand_resource):
        archive = mock_stage_archive()
        composite_stage = StageComposite()
        root_stage = Stage(archive.url)
        composite_stage.append(root_stage)

        resource_dst_name = 'resource-dst-name.sh'
        test_resource_fetcher = spack.fetch_strategy.from_kwargs(
            url=_file_prefix + mock_noexpand_resource, expand=False)
        test_resource = Resource('test_resource', test_resource_fetcher,
                                 resource_dst_name, None)
        resource_stage = ResourceStage(test_resource_fetcher, root_stage,
                                       test_resource)
        composite_stage.append(resource_stage)

        composite_stage.create()
        composite_stage.fetch()
        composite_stage.expand_archive()
        assert composite_stage.expanded  # Archive is expanded

        assert os.path.exists(
            os.path.join(composite_stage.source_path, resource_dst_name))

    @pytest.mark.disable_clean_stage_check
    def test_composite_stage_with_expand_resource(
            self, composite_stage_with_expanding_resource):

        composite_stage, root_stage, resource_stage, mock_resource = (
            composite_stage_with_expanding_resource)

        composite_stage.create()
        composite_stage.fetch()
        composite_stage.expand_archive()

        assert composite_stage.expanded  # Archive is expanded

        for fname in mock_resource.files:
            file_path = os.path.join(root_stage.source_path, 'resource-dir',
                                     fname)
            assert os.path.exists(file_path)

        # Perform a little cleanup
        shutil.rmtree(root_stage.path)

    @pytest.mark.disable_clean_stage_check
    def test_composite_stage_with_expand_resource_default_placement(
            self, composite_stage_with_expanding_resource):
        """For a resource which refers to a compressed archive which expands
        to a directory, check that by default the resource is placed in
        the source_path of the root stage with the name of the decompressed
        directory.
        """

        composite_stage, root_stage, resource_stage, mock_resource = (
            composite_stage_with_expanding_resource)

        resource_stage.resource.placement = None

        composite_stage.create()
        composite_stage.fetch()
        composite_stage.expand_archive()

        for fname in mock_resource.files:
            file_path = os.path.join(root_stage.source_path, 'resource-expand',
                                     fname)
            assert os.path.exists(file_path)

        # Perform a little cleanup
        shutil.rmtree(root_stage.path)

    def test_setup_and_destroy_no_name_without_tmp(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url) as stage:
            check_setup(stage, None, archive)
        check_destroy(stage, None)

    @pytest.mark.parametrize('debug', [False, True])
    def test_fetch(self, mock_stage_archive, debug):
        archive = mock_stage_archive()
        with spack.config.override('config:debug', debug):
            with Stage(archive.url, name=self.stage_name) as stage:
                stage.fetch()
                check_setup(stage, self.stage_name, archive)
                check_fetch(stage, self.stage_name)
            check_destroy(stage, self.stage_name)

    def test_no_search_if_default_succeeds(self, mock_stage_archive,
                                           failing_search_fn):
        archive = mock_stage_archive()
        stage = Stage(archive.url,
                      name=self.stage_name,
                      search_fn=failing_search_fn)
        with stage:
            stage.fetch()
        check_destroy(stage, self.stage_name)

    def test_no_search_mirror_only(self, failing_fetch_strategy,
                                   failing_search_fn):
        stage = Stage(failing_fetch_strategy,
                      name=self.stage_name,
                      search_fn=failing_search_fn)
        with stage:
            try:
                stage.fetch(mirror_only=True)
            except spack.fetch_strategy.FetchError:
                pass
        check_destroy(stage, self.stage_name)

    @pytest.mark.parametrize(
        "err_msg,expected",
        [('Fetch from fetch.test.com', 'Fetch from fetch.test.com'),
         (None, 'All fetchers failed')])
    def test_search_if_default_fails(self, failing_fetch_strategy, search_fn,
                                     err_msg, expected):
        stage = Stage(failing_fetch_strategy,
                      name=self.stage_name,
                      search_fn=search_fn)

        with stage:
            with pytest.raises(spack.fetch_strategy.FetchError,
                               match=expected):
                stage.fetch(mirror_only=False, err_msg=err_msg)

        check_destroy(stage, self.stage_name)
        assert search_fn.performed_search

    def test_ensure_one_stage_entry(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url, name=self.stage_name) as stage:
            stage.fetch()
            stage_path = get_stage_path(stage, self.stage_name)
            spack.fetch_strategy._ensure_one_stage_entry(stage_path)
        check_destroy(stage, self.stage_name)

    @pytest.mark.parametrize(
        "expected_file_list",
        [[], [_include_readme], [_include_extra, _include_readme],
         [_include_hidden, _include_readme]])
    def test_expand_archive(self, expected_file_list, mock_stage_archive):
        archive = mock_stage_archive(expected_file_list)
        with Stage(archive.url, name=self.stage_name) as stage:
            stage.fetch()
            check_setup(stage, self.stage_name, archive)
            check_fetch(stage, self.stage_name)
            stage.expand_archive()
            check_expand_archive(stage, self.stage_name, expected_file_list)
        check_destroy(stage, self.stage_name)

    def test_expand_archive_extra_expand(self, mock_stage_archive):
        """Test expand with an extra expand after expand (i.e., no-op)."""
        archive = mock_stage_archive()
        with Stage(archive.url, name=self.stage_name) as stage:
            stage.fetch()
            check_setup(stage, self.stage_name, archive)
            check_fetch(stage, self.stage_name)
            stage.expand_archive()
            stage.fetcher.expand()
            check_expand_archive(stage, self.stage_name, [_include_readme])
        check_destroy(stage, self.stage_name)

    def test_restage(self, mock_stage_archive):
        archive = mock_stage_archive()
        with Stage(archive.url, name=self.stage_name) as stage:
            stage.fetch()
            stage.expand_archive()

            with working_dir(stage.source_path):
                check_expand_archive(stage, self.stage_name, [_include_readme])

                # Try to make a file in the old archive dir
                with open('foobar', 'w') as file:
                    file.write("this file is to be destroyed.")

            assert 'foobar' in os.listdir(stage.source_path)

            # Make sure the file is not there after restage.
            stage.restage()
            check_fetch(stage, self.stage_name)
            assert 'foobar' not in os.listdir(stage.source_path)
        check_destroy(stage, self.stage_name)

    def test_no_keep_without_exceptions(self, mock_stage_archive):
        archive = mock_stage_archive()
        stage = Stage(archive.url, name=self.stage_name, keep=False)
        with stage:
            pass
        check_destroy(stage, self.stage_name)

    @pytest.mark.disable_clean_stage_check
    def test_keep_without_exceptions(self, mock_stage_archive):
        archive = mock_stage_archive()
        stage = Stage(archive.url, name=self.stage_name, keep=True)
        with stage:
            pass
        path = get_stage_path(stage, self.stage_name)
        assert os.path.isdir(path)

    @pytest.mark.disable_clean_stage_check
    def test_no_keep_with_exceptions(self, mock_stage_archive):
        class ThisMustFailHere(Exception):
            pass

        archive = mock_stage_archive()
        stage = Stage(archive.url, name=self.stage_name, keep=False)
        try:
            with stage:
                raise ThisMustFailHere()

        except ThisMustFailHere:
            path = get_stage_path(stage, self.stage_name)
            assert os.path.isdir(path)

    @pytest.mark.disable_clean_stage_check
    def test_keep_exceptions(self, mock_stage_archive):
        class ThisMustFailHere(Exception):
            pass

        archive = mock_stage_archive()
        stage = Stage(archive.url, name=self.stage_name, keep=True)
        try:
            with stage:
                raise ThisMustFailHere()

        except ThisMustFailHere:
            path = get_stage_path(stage, self.stage_name)
            assert os.path.isdir(path)

    def test_source_path_available(self, mock_stage_archive):
        """Ensure source path available but does not exist on instantiation."""
        archive = mock_stage_archive()
        stage = Stage(archive.url, name=self.stage_name)

        source_path = stage.source_path
        assert source_path
        assert source_path.endswith(spack.stage._source_path_subdir)
        assert not os.path.exists(source_path)

    @pytest.mark.skipif(sys.platform == 'win32',
                        reason="Not supported on Windows (yet)")
    @pytest.mark.skipif(getuid() == 0, reason='user is root')
    def test_first_accessible_path(self, tmpdir):
        """Test _first_accessible_path names."""
        spack_dir = tmpdir.join('paths')
        name = str(spack_dir)
        files = [os.path.join(os.path.sep, 'no', 'such', 'path'), name]

        # Ensure the tmpdir path is returned since the user should have access
        path = spack.stage._first_accessible_path(files)
        assert path == name
        assert os.path.isdir(path)
        check_stage_dir_perms(str(tmpdir), path)

        # Ensure an existing path is returned
        spack_subdir = spack_dir.join('existing').ensure(dir=True)
        subdir = str(spack_subdir)
        path = spack.stage._first_accessible_path([subdir])
        assert path == subdir

        # Ensure a path with a `$user` node has the right permissions
        # for its subdirectories.
        user = getpass.getuser()
        user_dir = spack_dir.join(user, 'has', 'paths')
        user_path = str(user_dir)
        path = spack.stage._first_accessible_path([user_path])
        assert path == user_path
        check_stage_dir_perms(str(tmpdir), path)

        # Cleanup
        shutil.rmtree(str(name))

    @pytest.mark.skipif(sys.platform == 'win32',
                        reason="Not supported on Windows (yet)")
    def test_create_stage_root(self, tmpdir, no_path_access):
        """Test create_stage_root permissions."""
        test_dir = tmpdir.join('path')
        test_path = str(test_dir)

        try:
            if getpass.getuser() in str(test_path).split(os.sep):
                # Simply ensure directory created if tmpdir includes user
                spack.stage.create_stage_root(test_path)
                assert os.path.exists(test_path)

                p_stat = os.stat(test_path)
                assert p_stat.st_mode & stat.S_IRWXU == stat.S_IRWXU
            else:
                # Ensure an OS Error is raised on created, non-user directory
                with pytest.raises(OSError) as exc_info:
                    spack.stage.create_stage_root(test_path)

                assert exc_info.value.errno == errno.EACCES
        finally:
            try:
                shutil.rmtree(test_path)
            except OSError:
                pass

    @pytest.mark.nomockstage
    def test_create_stage_root_bad_uid(self, tmpdir, monkeypatch):
        """
        Test the code path that uses an existing user path -- whether `$user`
        in `$tempdir` or not -- and triggers the generation of the UID
        mismatch warning.

        This situation can happen with some `config:build_stage` settings
        for teams using a common service account for installing software.
        """
        orig_stat = os.stat

        class MinStat:
            st_mode = -1
            st_uid = -1

        def _stat(path):
            p_stat = orig_stat(path)

            fake_stat = MinStat()
            fake_stat.st_mode = p_stat.st_mode
            return fake_stat

        user_dir = tmpdir.join(getpass.getuser())
        user_dir.ensure(dir=True)
        user_path = str(user_dir)

        # TODO: If we could guarantee access to the monkeypatch context
        # function (i.e., 3.6.0 on), the call and assertion could be moved
        # to a with block, such as:
        #
        #  with monkeypatch.context() as m:
        #      m.setattr(os, 'stat', _stat)
        #      spack.stage.create_stage_root(user_path)
        #      assert os.stat(user_path).st_uid != os.getuid()
        monkeypatch.setattr(os, 'stat', _stat)
        spack.stage.create_stage_root(user_path)

        # The following check depends on the patched os.stat as a poor
        # substitute for confirming the generated warnings.
        assert os.stat(user_path).st_uid != getuid()

    def test_resolve_paths(self):
        """Test _resolve_paths."""
        assert spack.stage._resolve_paths([]) == []

        # resolved path without user appends user
        paths = [os.path.join(os.path.sep, 'a', 'b', 'c')]
        user = getpass.getuser()
        can_paths = [os.path.join(paths[0], user)]
        assert spack.stage._resolve_paths(paths) == can_paths

        # resolved path with node including user does not append user
        paths = [os.path.join(os.path.sep, 'spack-{0}'.format(user), 'stage')]
        assert spack.stage._resolve_paths(paths) == paths

        tempdir = '$tempdir'
        can_tempdir = canonicalize_path(tempdir)
        user = getpass.getuser()
        temp_has_user = user in can_tempdir.split(os.sep)
        paths = [
            os.path.join(tempdir, 'stage'),
            os.path.join(tempdir, '$user'),
            os.path.join(tempdir, '$user', '$user'),
            os.path.join(tempdir, '$user', 'stage', '$user')
        ]

        res_paths = [canonicalize_path(p) for p in paths]
        if temp_has_user:
            res_paths[1] = can_tempdir
            res_paths[2] = os.path.join(can_tempdir, user)
            res_paths[3] = os.path.join(can_tempdir, 'stage', user)
        else:
            res_paths[0] = os.path.join(res_paths[0], user)

        assert spack.stage._resolve_paths(paths) == res_paths

    @pytest.mark.skipif(sys.platform == 'win32',
                        reason="Not supported on Windows (yet)")
    @pytest.mark.skipif(getuid() == 0, reason='user is root')
    def test_get_stage_root_bad_path(self, clear_stage_root):
        """Ensure an invalid stage path root raises a StageError."""
        with spack.config.override('config:build_stage', '/no/such/path'):
            with pytest.raises(spack.stage.StageError,
                               match="No accessible stage paths in"):
                spack.stage.get_stage_root()

        # Make sure the cached stage path values are unchanged.
        assert spack.stage._stage_root is None

    @pytest.mark.parametrize(
        'path,purged', [('spack-stage-1234567890abcdef1234567890abcdef', True),
                        ('spack-stage-anything-goes-here', True),
                        ('stage-spack', False)])
    def test_stage_purge(self, tmpdir, clear_stage_root, path, purged):
        """Test purging of stage directories."""
        stage_dir = tmpdir.join('stage')
        stage_path = str(stage_dir)

        test_dir = stage_dir.join(path)
        test_dir.ensure(dir=True)
        test_path = str(test_dir)

        with spack.config.override('config:build_stage', stage_path):
            stage_root = spack.stage.get_stage_root()
            assert stage_path == stage_root

            spack.stage.purge()

            if purged:
                assert not os.path.exists(test_path)
            else:
                assert os.path.exists(test_path)
                shutil.rmtree(test_path)

    def test_stage_constructor_no_fetcher(self):
        """Ensure Stage constructor with no URL or fetch strategy fails."""
        with pytest.raises(ValueError):
            with Stage(None):
                pass

    def test_stage_constructor_with_path(self, tmpdir):
        """Ensure Stage constructor with a path uses it."""
        testpath = str(tmpdir)
        with Stage('file:///does-not-exist', path=testpath) as stage:
            assert stage.path == testpath

    def test_diystage_path_none(self):
        """Ensure DIYStage for path=None behaves as expected."""
        with pytest.raises(ValueError):
            DIYStage(None)

    def test_diystage_path_invalid(self):
        """Ensure DIYStage for an invalid path behaves as expected."""
        with pytest.raises(spack.stage.StagePathError):
            DIYStage('/path/does/not/exist')

    def test_diystage_path_valid(self, tmpdir):
        """Ensure DIYStage for a valid path behaves as expected."""
        path = str(tmpdir)
        stage = DIYStage(path)
        assert stage.path == path
        assert stage.source_path == path

        # Order doesn't really matter for DIYStage since they are
        # basically NOOPs; however, call each since they are part
        # of the normal stage usage and to ensure full test coverage.
        stage.create()  # Only sets the flag value
        assert stage.created

        stage.cache_local()  # Only outputs a message
        stage.fetch()  # Only outputs a message
        stage.check()  # Only outputs a message
        stage.expand_archive()  # Only outputs a message

        assert stage.expanded  # The path/source_path does exist

        with pytest.raises(spack.stage.RestageError):
            stage.restage()

        stage.destroy()  # A no-op
        assert stage.path == path  # Ensure can still access attributes
        assert os.path.exists(stage.source_path)  # Ensure path still exists

    def test_diystage_preserve_file(self, tmpdir):
        """Ensure DIYStage preserves an existing file."""
        # Write a file to the temporary directory
        fn = tmpdir.join(_readme_fn)
        fn.write(_readme_contents)

        # Instantiate the DIYStage and ensure the above file is unchanged.
        path = str(tmpdir)
        stage = DIYStage(path)
        assert os.path.isdir(path)
        assert os.path.isfile(str(fn))

        stage.create()  # Only sets the flag value

        readmefn = str(fn)
        assert os.path.isfile(readmefn)
        with open(readmefn) as _file:
            _file.read() == _readme_contents