TEST: remove very slow test, add it as a comment to the code snippet it tests

1 files changed, 18 insertions, 1 deletions

diff --git a/numpy/core/src/multiarray/convert.c b/numpy/core/src/multiarray/convert.c
index ef231587d..e99bc3fe4 100644
--- a/numpy/core/src/multiarray/convert.c
+++ b/numpy/core/src/multiarray/convert.c
@@ -157,7 +157,24 @@ PyArray_ToFile(PyArrayObject *self, FILE *fp, char *sep, char *format)
             NPY_BEGIN_ALLOW_THREADS;
 
 #if defined (_MSC_VER) && defined(_WIN64)
-            /* Workaround Win64 fwrite() bug. Ticket #1660 */
+            /* Workaround Win64 fwrite() bug. Issue gh-2556
+             * If you touch this code, please run this test which is so slow
+             * it was removed from the test suite
+             *
+             * fourgbplus = 2**32 + 2**16
+             * testbytes = np.arange(8, dtype=np.int8)
+             * n = len(testbytes)
+             * flike = tempfile.NamedTemporaryFile()
+             * f = flike.file
+             * np.tile(testbytes, fourgbplus // testbytes.nbytes).tofile(f)
+             * flike.seek(0)
+             * a = np.fromfile(f, dtype=np.int8)
+             * flike.close()
+             * assert_(len(a) == fourgbplus)
+             * # check only start and end for speed:
+             * assert_((a[:n] == testbytes).all())
+             * assert_((a[-n:] == testbytes).all())
+             */
             {
                 npy_intp maxsize = 2147483648 / PyArray_DESCR(self)->elsize;
                 npy_intp chunksize;