src/HOL/Tools/Nitpick/nitpick_tests.ML

--- a/src/HOL/Tools/Nitpick/nitpick_tests.ML	Sun Aug 14 12:26:09 2016 +0200
+++ b/src/HOL/Tools/Nitpick/nitpick_tests.ML	Sun Aug 14 12:26:09 2016 +0200
@@ -217,7 +217,7 @@
     case Kodkod.solve_any_problem debug overlord timeout max_threads max_solutions
                                   (map (problem_for_nut @{context}) tests) of
       Kodkod.Normal ([], _, _) => ()
-    | _ => error "Tests failed."
+    | _ => error "Tests failed"
   end
 
 end;