slightly extend DEF test

tests/run/ct_DEF.pyx

@@ -42,7 +42,7 @@ DEF INT_TUPLE1 = TUPLE[:2]
 DEF INT_TUPLE2 = TUPLE[1:4:2]
 DEF ELLIPSIS = ...
 DEF EXPRESSION = int(float(2*2)) + int(str(2)) + int(max(1,2,3)) + sum([TWO, FIVE])
-DEF UNICODE_EXPRESSION = unicode(b'abc'.decode('utf8')).encode('ascii').decode('latin1')
+DEF UNICODE_EXPRESSION = unicode(BYTES.decode('utf8')).encode('ascii').decode('latin1')
 
 
 def c():
@@ -221,7 +221,7 @@ def expression():
 def unicode_expression():
     """
     >>> print(unicode_expression())
-    abc
+    spam
     """
     s = UNICODE_EXPRESSION
     return s