diff --git a/tests/support/util.tcl b/tests/support/util.tcl
index 48d06b741575f31839371b8a7ae962d47f8d1c7f..c5a6853b39be7d88eb4ad7587723d45ed7f2e390 100644
--- a/tests/support/util.tcl
+++ b/tests/support/util.tcl
@@ -91,10 +91,12 @@ proc wait_for_sync r {
     }
 }
 
+# Random integer between 0 and max (excluded).
 proc randomInt {max} {
     expr {int(rand()*$max)}
 }
 
+# Random signed integer between -max and max (both extremes excluded).
 proc randomSignedInt {max} {
     set i [randomInt $max]
     if {rand() > 0.5} {