diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index 889683b..0fa428f 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -15,6 +15,11 @@ jobs:
           - 5.0.0
           - 4.14.0
           - 4.04.1
+        include:
+          - lwt: true
+          - async: true
+          - eio: true
+            ocaml-version: 5.0.0
 
     runs-on: ${{ matrix.os }}
 
@@ -35,6 +40,7 @@ jobs:
           opam exec -- dune runtest zmq
 
       - name: zmq-lwt
+        if: matrix.lwt
         run: |
           opam pin add zmq-lwt.dev . --no-action
           opam install --deps-only --with-doc --with-test zmq-lwt
@@ -42,6 +48,7 @@ jobs:
           opam exec -- dune runtest zmq-lwt
 
       - name: zmq-async
+        if: matrix.async
         run: |
           opam pin add zmq-async.dev . --no-action
           opam install --deps-only --with-doc --with-test zmq-async
@@ -49,7 +56,7 @@ jobs:
           opam exec -- dune runtest zmq-async
 
       - name: zmq-eio
-        if: ${{ matrix.ocaml-version == '5.0.0' }}
+        if: matrix.eio
         run: |
           opam pin add zmq-eio.dev . --no-action
           opam install --deps-only --with-doc --with-test zmq-eio
diff --git a/zmq-eio/test/test.ml b/zmq-eio/test/test.ml
index 8845fea..503216d 100644
--- a/zmq-eio/test/test.ml
+++ b/zmq-eio/test/test.ml
@@ -1,6 +1,5 @@
 open OUnit
 
-(** Sleep is horrible slow, or causing strange slowdowns *)
 let sleepf env secs = Eio.Time.sleep (Eio.Stdenv.clock env) secs
 
 let setup ~sw env =