Attempt to catch MemoryError if possible

speedtest.py

@@ -743,11 +743,17 @@ class HTTPUploaderData(object):
         chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
         multiplier = int(round(int(self.length) / 36.0))
         IO = BytesIO or StringIO
+        try:
             self._data = IO(
                 ('content1=%s' %
                  (chars * multiplier)[0:int(self.length) - 9]
                  ).encode()
             )
+        except MemoryError:
+            raise SpeedtestCLIError(
+                'Insufficient memory to pre-allocate upload data. Please '
+                'use --no-pre-allocate'
+            )
 
     @property
     def data(self):