Added regression tests for #4655

1 files changed, 38 insertions, 1 deletions

diff --git a/numpy/fft/tests/test_fftpack.py b/numpy/fft/tests/test_fftpack.py
index 50702ab3c..13db3e682 100644
--- a/numpy/fft/tests/test_fftpack.py
+++ b/numpy/fft/tests/test_fftpack.py
@@ -1,7 +1,8 @@
 from __future__ import division, absolute_import, print_function
 
 import numpy as np
-from numpy.testing import TestCase, run_module_suite, assert_array_almost_equal
+from numpy.testing import TestCase, run_module_suite, assert_array_equal, assert_array_almost_equal
+import threading, Queue
 
 def fft1(x):
     L = len(x)
@@ -23,5 +24,41 @@ class TestFFT1D(TestCase):
         assert_array_almost_equal(fft1(x), np.fft.fft(x))
 
 
+class TestFFTThreadSafe(TestCase):
+    threads = 32
+    input_shape = (1000, 1000)
+
+    def _test_mtsame(self, func, *args):
+        def worker(args, q):
+            q.put(func(*args))
+
+        q = Queue.Queue()
+        expected = func(*args)
+
+        # Spin off a bunch of threads to call the same function simultaneously
+        for i in xrange(self.threads):
+            threading.Thread(target=worker, args=(args, q)).start()
+
+        # Make sure all threads returned the correct value
+        for i in xrange(self.threads):
+            assert_array_equal(q.get(), expected, 'Function returned wrong value in multithreaded context')
+
+    def test_fft(self):
+        a = np.ones(self.input_shape) * 1+0j
+        self._test_mtsame(np.fft.fft, a)
+
+    def test_ifft(self):
+        a = np.ones(self.input_shape) * 1+0j
+        self._test_mtsame(np.fft.ifft, a)
+
+    def test_rfft(self):
+        a = np.ones(self.input_shape)
+        self._test_mtsame(np.fft.rfft, a)
+
+    def test_irfft(self):
+        a = np.ones(self.input_shape) * 1+0j
+        self._test_mtsame(np.fft.irfft, a)
+
+
 if __name__ == "__main__":
     run_module_suite()