def test_to_data_frame_index(index):
"""Test index creation in stc Pandas exporter."""
n_vert, n_times = 10, 5
vertices = [np.arange(n_vert, dtype=np.int), np.empty(0, dtype=np.int)]
data = rng.randn(n_vert, n_times)
stc = SourceEstimate(data, vertices=vertices, tmin=0, tstep=1,
subject='sample')
df = stc.to_data_frame(index=index)
# test index setting
if not isinstance(index, list):
index = [index]
assert (df.index.names == index)
# test that non-indexed data were present as columns
non_index = list(set(['time', 'subject']) - set(index))
if len(non_index):
assert all(np.in1d(non_index, df.columns))
