diff --git a/collects/tests/mzscheme/net.ss b/collects/tests/mzscheme/net.ss
index 4f6b3cc86d..86d6daa7e2 100644
--- a/collects/tests/mzscheme/net.ss
+++ b/collects/tests/mzscheme/net.ss
@@ -252,6 +252,13 @@
   (test-s->u #("a+b-c456.d" #f "www.foo.com" #f #t (#("")) () #f)
              "a+b-c456.d://www.foo.com/")
 
+  ;; a colon can appear in absolute paths
+  (test-s->u #(#f #f #f #f #t (#("x:y") #("z")) () #f)
+             "/x:y/z")
+  ;; and in relative paths as long as it's not in the first element
+  (test-s->u #(#f #f #f #f #f (#("x") #("y:z")) () #f)
+             "x/y:z")
+
   ;; test bad schemes
   (err/rt-test (string->url "://www.foo.com/") url-exception?)
   (err/rt-test (string->url "9://www.foo.com/") url-exception?)