diff --git a/tiny_httpd.opam b/tiny_httpd.opam
index 367c6d12..7409ccee 100644
--- a/tiny_httpd.opam
+++ b/tiny_httpd.opam
@@ -17,6 +17,7 @@ depends: [
   "ocaml" { >= "4.05.0" }
   "odoc" {with-doc}
   "conf-libcurl" {with-test}
+  "ptime" {with-test}
   "qcheck-core" {with-test & >= "0.9" }
   "ptime" {with-test}
 ]