diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 78613ae8..e193f8f5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -32,7 +32,7 @@ jobs:
           ocaml-compiler: ${{ matrix.ocaml-compiler }}
           opam-depext-flags: --with-test
 
-      - run: opam install . --deps-only --with-test
+      - run: opam install ./tiny_httpd.opam ./tiny_httpd_camlzip.opam --deps-only --with-test
 
       - run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip