TST: Add test to simulate running update() simultaneously

Author: mgxd

templateflow/tests/test_multiproc.py

@@ -0,0 +1,26 @@
+import os
+from concurrent.futures import ProcessPoolExecutor
+
+import pytest
+
+CPUs = os.cpu_count() or 1
+
+
+def _update():
+    from templateflow.conf import update
+
+    update(local=False, overwrite=True, silent=True)
+    return True
+
+@pytest.mark.skipif(CPUs < 2, reason='At least 2 CPUs are required')
+def test_multi_proc_update(tmp_path, monkeypatch):
+    tf_home = tmp_path / 'tf_home'
+    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(tf_home))
+
+    futs = []
+    with ProcessPoolExecutor(max_workers=2) as executor:
+        for _ in range(2):
+            futs.append(executor.submit(_update))
+
+    for fut in futs:
+        assert fut.result()