diff --git a/tests/debugger/completion.inputrc b/tests/debugger/completion.inputrc
index 9c0e12b6d..ba1cbaedd 100644
--- a/tests/debugger/completion.inputrc
+++ b/tests/debugger/completion.inputrc
@@ -8,5 +8,8 @@ set show-all-if-ambiguous on
 # Disable --More-- prompt when completion list fills screen.
 set page-completions off
 
+# Make sure a standardized screen width is used.
+set completion-display-width 80
+
 # Make the completion requests show up in the input file.
 @: complete