diff --git a/graph-lib/lib/debug-syntax.rkt b/graph-lib/lib/debug-syntax.rkt
index df0be259..a59f2996 100644
--- a/graph-lib/lib/debug-syntax.rkt
+++ b/graph-lib/lib/debug-syntax.rkt
@@ -17,4 +17,9 @@
 (require 'm-browse-syntax)
 (provide browse-syntax
          browse-syntaxes
-         debug-syntax)
\ No newline at end of file
+         debug-syntax)
+
+;; Avoid problems with raco test on headless machines (GTK tries to open
+;; display :0 otherwise)
+(module main racket)
+(module test racket)
\ No newline at end of file