+1

Author: skirpichev

Lib/test/test_struct.py

@@ -935,12 +935,13 @@ def test_half_float(self):
             self.assertTrue(math.isnan(struct.unpack('<e', bits)[0]))
             self.assertTrue(math.isnan(struct.unpack('>e', bits[::-1])[0]))
 
-            if sys.platform != 'win32':
-                # Check round-trip for NaN's:
-                nan = struct.unpack('<e', bits)[0]
-                self.assertEqual(struct.pack('<e', nan), bits)
-                nan = struct.unpack('>e', bits[::-1])[0]
-                self.assertEqual(struct.pack('>e', nan), bits[::-1])
+            # Check round-trip for NaN's:
+            if sys.platform == 'win32' and int.from_bytes(bits[::-1]) & (1<<9):
+                continue  # doesn't work for sNaN's here
+            nan = struct.unpack('<e', bits)[0]
+            self.assertEqual(struct.pack('<e', nan), bits)
+            nan = struct.unpack('>e', bits[::-1])[0]
+            self.assertEqual(struct.pack('>e', nan), bits[::-1])
 
         # Check that packing produces a bit pattern representing a quiet NaN:
         # all exponent bits and the msb of the fraction should all be 1.