TST: add a test in a new test_multithreading module

ngoldbaum · ngoldbaum · commit 38e3e0f86cba · 2024-04-18T09:09:08.000-06:00
diff --git a/numpy/_core/tests/test_multithreading.py b/numpy/_core/tests/test_multithreading.py
@@ -0,0 +1,15 @@
+import concurrent.futures
+
+import numpy as np
+
+
+def test_parallel_errstate_creation():
+    # if the coercion cache is enabled and not thread-safe, creating RandomState
+    # instances simultaneously leads to a data race
+    def func(seed):
+        np.random.RandomState(seed)
+
+    with concurrent.futures.ThreadPoolExecutor(max_workers=8) as tpe:
+        futures = [tpe.submit(func, i) for i in range(500)]
+        for f in futures:
+            f.result()
