Add test per report gh-109

Author: oleksandr-pavlyk

mkl_fft/tests/test_fftnd.py

@@ -217,3 +217,14 @@ def test_scale_nd_axes(self):
 
         r_tol, a_tol = _get_rtol_atol(X)
         assert_allclose(f, 5*f_scale, rtol=r_tol, atol=a_tol)
+
+
+def test_gh109():
+    b_int = np.array([[5, 7, 6, 5], [4, 6, 4, 8], [9, 3, 7, 5]], dtype=np.int64)
+    b = np.asarray(b_int, dtype=np.float32)
+
+    r1 = mkl_fft.fftn(b, shape=None, axes=(0,), overwrite_x=False)
+    r2 = mkl_fft.fftn(b_int, shape=None, axes=(0,), overwrite_x=False)
+
+    rtol, atol = _get_rtol_atol(b)
+    assert_allclose(r1, r2, rtol=rtol, atol=atol)