fix tests

Author: cxzhong

src/sage/libs/gap/element.pyx

@@ -2483,7 +2483,12 @@ cdef class GapElement_Function(GapElement):
             sage: rnd=[1,2,3]
             sage: libgap.Sum(rnd)
             6
-
+            
+            sage: for i in range(100):
+            ....:     rnd = [ randint(-10,10) for i in range(randint(0,7)) ]
+            ....:     # compute the sum in GAP
+            ....:     _ = libgap.Sum(rnd)
+            
             sage: libgap_exec = libgap.eval("Exec")
             sage: libgap_exec('echo hello from the shell')
             hello from the shell