diff --git a/collects/tests/compiler/zo-exs.rkt b/collects/tests/compiler/zo-exs.rkt
new file mode 100644
index 0000000000..b8ab07e067
--- /dev/null
+++ b/collects/tests/compiler/zo-exs.rkt
@@ -0,0 +1,22 @@
+#lang racket
+(require compiler/zo-parse
+         compiler/zo-marshal
+         tests/eli-tester)
+
+(define (roundtrip ct)
+  (define bs (zo-marshal ct))
+  (test bs
+        (zo-parse (open-input-bytes bs)) => ct))
+
+(test
+ (local [(define (hash-test make-hash-placeholder)
+           (roundtrip 
+            (compilation-top 0 
+                             (prefix 0 empty empty)
+                             (local [(define ht-ph (make-placeholder #f))
+                                     (define ht (make-hash-placeholder (list (cons 'g ht-ph))))]
+                               (placeholder-set! ht-ph ht)
+                               (make-reader-graph ht)))))]
+   (hash-test make-hash-placeholder)
+   (hash-test make-hasheq-placeholder)
+   (hash-test make-hasheqv-placeholder)))