ENH check that run_onsets does not give empty runs

Author: TomDLT

voxelwise_tutorials/tests/test_mappers.py

@@ -1,6 +1,6 @@
 """Unit tests on the mappers.
 
-Requires the movies 4T dataset locally.
+Requires the movies 3T dataset locally.
 """
 
 import os

voxelwise_tutorials/tests/test_utils.py

@@ -0,0 +1,22 @@
+import numpy as np
+import pytest
+from voxelwise_tutorials.utils import generate_leave_one_run_out
+
+
+def test_generate_leave_one_run_out_disjoint():
+    n_samples = 40
+    run_onsets = [0, 10, 20, 30]
+
+    for train, val in generate_leave_one_run_out(n_samples, run_onsets):
+        assert len(train) > 0
+        assert len(val) > 0
+        assert not np.any(np.isin(train, val))
+        assert not np.any(np.isin(val, train))
+
+
+@pytest.mark.parametrize("run_onsets",
+                         [[0, 10, 20, 30, 40], [0, 10, 20, 20, 30]])
+def test_generate_leave_one_run_out_empty_runs(run_onsets):
+    n_samples = 40
+    with pytest.raises(ValueError):
+        list(generate_leave_one_run_out(n_samples, run_onsets))

voxelwise_tutorials/utils.py

@@ -38,6 +38,10 @@ def generate_leave_one_run_out(n_samples, run_onsets, random_state=None,
 
     all_samples = np.arange(n_samples)
     runs = np.split(all_samples, run_onsets[1:])
+    if any(len(run) == 0 for run in runs):
+        raise ValueError("Some runs have no samples. Check that run_onsets "
+                         "does not include any repeated index, nor the last "
+                         "index.")
 
     for val_runs in all_val_runs.T:
         train = np.hstack(