diff --git a/lib/testsuite.in b/lib/testsuite.in
index 0d3924ca7f2c94737e63083609bdaaf5f94244fd..51f086a847d6259929657ac5abbec49fffee0a38 100644
--- a/lib/testsuite.in
+++ b/lib/testsuite.in
@@ -25,6 +25,8 @@ test_eq(dirname("a"),"")
 
 test_eq( catch(error("x"))[0], "x" )
 test_eq( catch(error("X"))[1][0]->fun, master()->_main )
+test_eq( catch(error("%x", 10))[0], "a" )
+test_eval_error( error("%s", 0) )
 
 test_true( true )
 test_false( false )