def test_source_space_from_label():
    """Test generating a source space from volume label."""
    tempdir = _TempDir()
    aseg_fname = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')
    label_names = get_volume_labels_from_aseg(aseg_fname)
    volume_label = label_names[int(np.random.rand() * len(label_names))]

    # Test pos as dict
    pos = dict()
    pytest.raises(ValueError, setup_volume_source_space, 'sample', pos=pos,
                  volume_label=volume_label, mri=aseg_fname)

    # Test no mri provided
    pytest.raises(RuntimeError, setup_volume_source_space, 'sample', mri=None,
                  volume_label=volume_label)

    # Test invalid volume label
    pytest.raises(ValueError, setup_volume_source_space, 'sample',
                  volume_label='Hello World!', mri=aseg_fname)

    src = setup_volume_source_space('sample', subjects_dir=subjects_dir,
                                    volume_label=volume_label, mri=aseg_fname,
                                    add_interpolator=False)
    assert_equal(volume_label, src[0]['seg_name'])

    # test reading and writing
    out_name = op.join(tempdir, 'temp-src.fif')
    write_source_spaces(out_name, src)
    src_from_file = read_source_spaces(out_name)
    _compare_source_spaces(src, src_from_file, mode='approx')

def test_volume_labels_morph(tmpdir):
    """Test generating a source space from volume label."""
    # see gh-5224
    evoked = mne.read_evokeds(fname_evoked)[0].crop(0, 0)
    evoked.pick_channels(evoked.ch_names[:306:8])
    evoked.info.normalize_proj()
    n_ch = len(evoked.ch_names)
    aseg_fname = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')
    label_names = get_volume_labels_from_aseg(aseg_fname)
    src = setup_volume_source_space(
        'sample', subjects_dir=subjects_dir, volume_label=label_names[:2],
        mri=aseg_fname)
    assert len(src) == 2
    assert src.kind == 'volume'
    n_src = sum(s['nuse'] for s in src)
    sphere = make_sphere_model('auto', 'auto', evoked.info)
    fwd = make_forward_solution(evoked.info, fname_trans, src, sphere)
    assert fwd['sol']['data'].shape == (n_ch, n_src * 3)
    inv = make_inverse_operator(evoked.info, fwd, make_ad_hoc_cov(evoked.info),
                                loose=1.)
    stc = apply_inverse(evoked, inv)
    assert stc.data.shape == (n_src, 1)
    img = stc.as_volume(src, mri_resolution=True)
    n_on = np.array(img.dataobj).astype(bool).sum()
    assert n_on == 291  # was 291 on `master` before gh-5590
    img = stc.as_volume(src, mri_resolution=False)
    n_on = np.array(img.dataobj).astype(bool).sum()
    assert n_on == 44  # was 20 on `master` before gh-5590

def test_get_volume_label_names():
    """Test reading volume label names."""
    aseg_fname = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')
    label_names, label_colors = get_volume_labels_from_aseg(aseg_fname,
                                                            return_colors=True)
    assert_equal(label_names.count('Brain-Stem'), 1)

    assert_equal(len(label_colors), len(label_names))

def test_get_volume_label_names():
    """Test reading volume label names
    """
    aseg_fname = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')

    label_names = get_volume_labels_from_aseg(aseg_fname)

    assert_equal(label_names.count('Brain-Stem'), 1)

def test_forward_mixed_source_space():
    """Test making the forward solution for a mixed source space
    """
    # get bem file
    fname_bem = op.join(subjects_dir, 'sample', 'bem',
                        'sample-5120-5120-5120-bem-sol.fif')
    # get the aseg file
    fname_aseg = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')

    # get the surface source space
    surf = setup_source_space('sample', fname=None, spacing='ico2')

    # setup two volume source spaces
    label_names = get_volume_labels_from_aseg(fname_aseg)
    vol_labels = [label_names[int(np.random.rand() * len(label_names))]
                  for _ in range(2)]
    vol1 = setup_volume_source_space('sample', fname=None, pos=20.,
                                     mri=fname_aseg,
                                     volume_label=vol_labels[0])
    vol2 = setup_volume_source_space('sample', fname=None, pos=20.,
                                     mri=fname_aseg,
                                     volume_label=vol_labels[1])

    # merge surfaces and volume
    src = surf + vol1 + vol2

    # calculate forward solution
    fwd = make_forward_solution(fname_raw, mri=fname_mri, src=src,
                                bem=fname_bem, fname=None)

    # extract source spaces
    src_from_fwd = fwd['src']

    # get the coordinate frame of each source space
    coord_frames = np.array([s['coord_frame'] for s in src_from_fwd])

    # assert that all source spaces are in head coordinates
    assert_true((coord_frames == FIFF.FIFFV_COORD_HEAD).all())

    # run tests for SourceSpaces.export_volume
    fname_img = op.join(temp_dir, 'temp-image.mgz')

    # head coordinates and mri_resolution, but trans file
    assert_raises(ValueError, src_from_fwd.export_volume, fname_img,
                  mri_resolution=True, trans=None)

    # head coordinates and mri_resolution, but wrong trans file
    vox_mri_t = vol1[0]['vox_mri_t']
    assert_raises(RuntimeError, src_from_fwd.export_volume, fname_img,
                  mri_resolution=True, trans=vox_mri_t)

def test_forward_mixed_source_space():
    """Test making the forward solution for a mixed source space
    """
    temp_dir = _TempDir()
    # get the surface source space
    surf = read_source_spaces(fname_src)

    # setup two volume source spaces
    label_names = get_volume_labels_from_aseg(fname_aseg)
    vol_labels = [label_names[int(np.random.rand() * len(label_names))]
                  for _ in range(2)]
    vol1 = setup_volume_source_space('sample', fname=None, pos=20.,
                                     mri=fname_aseg,
                                     volume_label=vol_labels[0],
                                     add_interpolator=False)
    vol2 = setup_volume_source_space('sample', fname=None, pos=20.,
                                     mri=fname_aseg,
                                     volume_label=vol_labels[1],
                                     add_interpolator=False)

    # merge surfaces and volume
    src = surf + vol1 + vol2

    # calculate forward solution
    fwd = make_forward_solution(fname_raw, fname_trans, src, fname_bem, None)
    assert_true(repr(fwd))

    # extract source spaces
    src_from_fwd = fwd['src']

    # get the coordinate frame of each source space
    coord_frames = np.array([s['coord_frame'] for s in src_from_fwd])

    # assert that all source spaces are in head coordinates
    assert_true((coord_frames == FIFF.FIFFV_COORD_HEAD).all())

    # run tests for SourceSpaces.export_volume
    fname_img = op.join(temp_dir, 'temp-image.mgz')

    # head coordinates and mri_resolution, but trans file
    assert_raises(ValueError, src_from_fwd.export_volume, fname_img,
                  mri_resolution=True, trans=None)

    # head coordinates and mri_resolution, but wrong trans file
    vox_mri_t = vol1[0]['vox_mri_t']
    assert_raises(ValueError, src_from_fwd.export_volume, fname_img,
                  mri_resolution=True, trans=vox_mri_t)

def test_combine_source_spaces():
    """Test combining source spaces."""
    tempdir = _TempDir()
    aseg_fname = op.join(subjects_dir, 'sample', 'mri', 'aseg.mgz')
    label_names = get_volume_labels_from_aseg(aseg_fname)
    volume_labels = [label_names[int(np.random.rand() * len(label_names))]
                     for ii in range(2)]

    # get a surface source space (no need to test creation here)
    srf = read_source_spaces(fname, patch_stats=False)

    # setup 2 volume source spaces
    vol = setup_volume_source_space('sample', subjects_dir=subjects_dir,
                                    volume_label=volume_labels[0],
                                    mri=aseg_fname, add_interpolator=False)

    # setup a discrete source space
    rr = rng.randint(0, 20, (100, 3)) * 1e-3
    nn = np.zeros(rr.shape)
    nn[:, -1] = 1
    pos = {'rr': rr, 'nn': nn}
    disc = setup_volume_source_space('sample', subjects_dir=subjects_dir,
                                     pos=pos, verbose='error')

    # combine source spaces
    src = srf + vol + disc

    # test addition of source spaces
    assert_equal(type(src), SourceSpaces)
    assert_equal(len(src), 4)

    # test reading and writing
    src_out_name = op.join(tempdir, 'temp-src.fif')
    src.save(src_out_name)
    src_from_file = read_source_spaces(src_out_name)
    _compare_source_spaces(src, src_from_file, mode='approx')
    assert_equal(repr(src), repr(src_from_file))
    assert_equal(src.kind, 'mixed')

    # test that all source spaces are in MRI coordinates
    coord_frames = np.array([s['coord_frame'] for s in src])
    assert (coord_frames == FIFF.FIFFV_COORD_MRI).all()

    # test errors for export_volume
    image_fname = op.join(tempdir, 'temp-image.mgz')

    # source spaces with no volume
    pytest.raises(ValueError, srf.export_volume, image_fname, verbose='error')

    # unrecognized source type
    disc2 = disc.copy()
    disc2[0]['type'] = 'kitty'
    src_unrecognized = src + disc2
    pytest.raises(ValueError, src_unrecognized.export_volume, image_fname,
                  verbose='error')

    # unrecognized file type
    bad_image_fname = op.join(tempdir, 'temp-image.png')
    # vertices outside vol space warning
    pytest.raises(ValueError, src.export_volume, bad_image_fname,
                  verbose='error')

    # mixed coordinate frames
    disc3 = disc.copy()
    disc3[0]['coord_frame'] = 10
    src_mixed_coord = src + disc3
    pytest.raises(ValueError, src_mixed_coord.export_volume, image_fname,
                  verbose='error')