diff --git a/tests/client/test_client_lib.ml b/tests/client/test_client_lib.ml
index ed5a1119..f595937e 100644
--- a/tests/client/test_client_lib.ml
+++ b/tests/client/test_client_lib.ml
@@ -11,7 +11,7 @@ let test_config_printing () =
     \ self_trace=false; url_traces=\"http://localhost:4318/v1/traces\";\n\
     \ url_metrics=\"http://localhost:4318/v1/metrics\";\n\
     \ url_logs=\"http://localhost:4318/v1/logs\"; headers=[]; batch_traces=400;\n\
-    \ batch_metrics=20; batch_logs=400; batch_timeout_ms=2000;\n\
+    \ batch_metrics=200; batch_logs=400; batch_timeout_ms=2000;\n\
     \ http_concurrency_level=None }"
   in
   check' string ~msg:"is rendered correctly" ~actual ~expected
diff --git a/tests/client_e2e/clients_e2e_lib.ml b/tests/client_e2e/clients_e2e_lib.ml
index 3466e9d1..b4781369 100644
--- a/tests/client_e2e/clients_e2e_lib.ml
+++ b/tests/client_e2e/clients_e2e_lib.ml
@@ -110,13 +110,14 @@ type params = {
   url: string;
   jobs: int;
   procs: int;
+  n_outer: int;
   batch_traces: int;
   batch_metrics: int;
   batch_logs: int;
   iterations: int;
 }
 
-let cmd exec params =
+let cmd exec params : string list =
   [
     exec;
     "-j";
@@ -125,6 +126,8 @@ let cmd exec params =
     string_of_int params.procs;
     "--url";
     params.url;
+    "-n";
+    string_of_int params.n_outer;
     "--iterations";
     string_of_int params.iterations;
     "--batch-traces";
@@ -151,21 +154,23 @@ let tests params signal_batches =
           ~msg:
             "number of occurrences should equal the configured jobs * the \
              configured processes"
-          ~expected:(params.jobs * params.procs)
+          ~expected:(params.jobs * params.procs * params.n_outer)
           ~actual:(count_spans_with_name "loop.outer" signals));
     test "loop.inner spans" (fun () ->
         Alcotest.(check' int)
           ~msg:
             "number of occurrences should equal the configured jobs * the  \
              configured iterations * configured processes"
-          ~expected:(params.jobs * params.iterations * params.procs)
+          ~expected:
+            (params.jobs * params.iterations * params.procs * params.n_outer)
           ~actual:(count_spans_with_name "loop.inner" signals));
     test "alloc spans" (fun () ->
         Alcotest.(check' int)
           ~msg:
             "number of occurrences should equal the configured jobs * the  \
              configured iterations * configured processes"
-          ~expected:(params.jobs * params.iterations * params.procs)
+          ~expected:
+            (params.jobs * params.iterations * params.procs * params.n_outer)
           ~actual:(count_spans_with_name "alloc" signals);
         Alcotest.(check' bool)
           ~msg:"should have 'done with alloc' event" ~expected:true
@@ -193,9 +198,10 @@ let tests params signal_batches =
     test "logs" (fun () ->
         Alcotest.(check' int)
           ~msg:
-            "should record jobs * iterations occurrences * configured \
+            "should record jobs * iterations occurrences * configured * n \
              processes of 'inner at n'"
-          ~expected:(params.jobs * params.iterations * params.procs)
+          ~expected:
+            (params.jobs * params.iterations * params.procs * params.n_outer)
           ~actual:
             (signals
             |> count_logs_with_body (function
@@ -205,16 +211,19 @@ let tests params signal_batches =
                  | _ -> false)));
   ]
 
-let run_tests ~port cmds =
+let run_tests ~port (cmds : _ list) : unit =
   let suites =
-    cmds
-    |> List.map (fun (exec, params) ->
+    let open Lwt.Syntax in
+    Lwt_main.run
+    @@ Lwt_list.map_s
+         (fun (exec, params) ->
            let cmd = cmd exec params in
-           let name = cmd |> String.concat " " in
-           let signal_batches = Signal_gatherer.gather_signals ~port cmd in
+           let name = Printf.sprintf "'test: %s'" (String.concat " " cmd) in
+           let* signal_batches = Signal_gatherer.gather_signals ~port cmd in
            (* Let server reset *)
-           Unix.sleep 1;
-           name, tests params signal_batches)
+           let* () = Lwt_unix.sleep 1. in
+           Lwt.return (name, tests params signal_batches))
+         cmds
   in
   let open Alcotest in
   run "Collector integration tests" suites
diff --git a/tests/client_e2e/dune b/tests/client_e2e/dune
index edd23b25..50286fa3 100644
--- a/tests/client_e2e/dune
+++ b/tests/client_e2e/dune
@@ -24,15 +24,15 @@
   (re_export containers)
   logs.fmt
   logs.threaded
-  lwt
-  lwt.unix
+  (re_export lwt)
+  (re_export lwt.unix)
   (re_export opentelemetry)
   (re_export opentelemetry-client)))
 
 (library
  (name clients_e2e_lib)
  (modules clients_e2e_lib)
- (libraries alcotest signal_gatherer))
+ (libraries alcotest lwt lwt.unix signal_gatherer))
 
 (tests
  (names test_cottp_lwt_client_e2e)
@@ -52,7 +52,16 @@
   (>= %{ocaml_version} 5.0))
  (libraries clients_e2e_lib alcotest opentelemetry opentelemetry-client))
 
+(tests
+ (names test_ocurl_client_e2e)
+ (modules test_ocurl_client_e2e)
+ (package opentelemetry-client-ocurl)
+ (deps %{bin:emit1})
+ (enabled_if
+  (>= %{ocaml_version} 5.0))
+ (libraries clients_e2e_lib alcotest opentelemetry opentelemetry-client))
+
 (executable
  (name signal_reporter_server)
  (modules signal_reporter_server)
- (libraries signal_gatherer))
+ (libraries signal_gatherer lwt lwt.unix))
diff --git a/tests/client_e2e/signal_gatherer.ml b/tests/client_e2e/signal_gatherer.ml
index 47fcbf41..40743232 100644
--- a/tests/client_e2e/signal_gatherer.ml
+++ b/tests/client_e2e/signal_gatherer.ml
@@ -116,9 +116,7 @@ let default_port =
   | [ _; _; port ] -> int_of_string port
   | _ -> failwith "unexpected format in Client.Config.default_url"
 
-let gather_signals ?(port = default_port) program_to_test =
-  Lwt_main.run
-  @@
+let gather_signals ?(port = default_port) program_to_test : _ Lwt.t =
   let stream, push = Lwt_stream.create () in
   let* () =
     Lwt.pick [ Server.run port push; Tested_program.run program_to_test ]
@@ -128,14 +126,15 @@ let gather_signals ?(port = default_port) program_to_test =
   Lwt_stream.to_list stream
 
 (* Just run the server, and print the signals gathered. *)
-let run ?(port = default_port) () =
-  Lwt_main.run
-  @@
+let run ?(port = default_port) () : _ Lwt.t =
   let stream, push = Lwt_stream.create () in
   Lwt.join
     [
       Server.run port push;
       Lwt_stream.iter_s
-        (fun s -> Format.asprintf "%a" Signal.Pp.pp s |> Lwt_io.printl)
+        (fun s ->
+          let open Lwt.Syntax in
+          let* () = Lwt_io.printl (Format.asprintf "%a" Signal.Pp.pp s) in
+          Lwt_io.flush Lwt_io.stdout)
         stream;
     ]
diff --git a/tests/client_e2e/signal_gatherer.mli b/tests/client_e2e/signal_gatherer.mli
index b948d059..165fc030 100644
--- a/tests/client_e2e/signal_gatherer.mli
+++ b/tests/client_e2e/signal_gatherer.mli
@@ -2,7 +2,7 @@
     server that can receive the signals make them available for inspection. *)
 
 val gather_signals :
-  ?port:int -> string list -> Opentelemetry_client.Signal.t list
+  ?port:int -> string list -> Opentelemetry_client.Signal.t list Lwt.t
 (** [gather_signals program_to_test] is a list of all the signals emitted by the
     [program_to_test], which the server was able to record. This function
     assumes that the program to test will be sending its signals to the
@@ -12,7 +12,7 @@ val gather_signals :
       the port where signals will be received. Default is port set in
       {!Opentelemetry_client.Config.default_url}. *)
 
-val run : ?port:int -> unit -> unit
+val run : ?port:int -> unit -> unit Lwt.t
 (** [run ()] runs a signal gathering server and prints all batches of signals
     received to stdout.
 
diff --git a/tests/client_e2e/signal_reporter_server.ml b/tests/client_e2e/signal_reporter_server.ml
index a7f17708..aed834a5 100644
--- a/tests/client_e2e/signal_reporter_server.ml
+++ b/tests/client_e2e/signal_reporter_server.ml
@@ -1,4 +1,4 @@
 (** Runs a signal gatherer server, and prints out every batch of signals
     received to stdout. This can be used to monitor the signals sent by an
     application, e.g., the test executables defined in /tests/bin/emit1*.ml *)
-let () = Signal_gatherer.run ()
+let () = Lwt_main.run @@ Signal_gatherer.run ()
diff --git a/tests/client_e2e/test_cottp_eio_client_e2e.ml b/tests/client_e2e/test_cottp_eio_client_e2e.ml
index ab5cf985..d093ed1b 100644
--- a/tests/client_e2e/test_cottp_eio_client_e2e.ml
+++ b/tests/client_e2e/test_cottp_eio_client_e2e.ml
@@ -16,6 +16,7 @@ let () =
           url;
           jobs = 1;
           procs = 1;
+          n_outer = 1;
           iterations = 1;
           batch_traces = 2;
           batch_metrics = 2;
@@ -26,16 +27,29 @@ let () =
           url;
           jobs = 3;
           procs = 1;
+          n_outer = 1;
           iterations = 1;
           batch_traces = 400;
           batch_metrics = 3;
           batch_logs = 400;
         } );
+      ( "emit1_eio",
+        {
+          url;
+          jobs = 3;
+          procs = 1;
+          n_outer = 5;
+          iterations = 1;
+          batch_traces = 100;
+          batch_metrics = 20;
+          batch_logs = 400;
+        } );
       ( "emit1_eio",
         {
           url;
           jobs = 3;
           procs = 3;
+          n_outer = 1;
           iterations = 1;
           batch_traces = 400;
           batch_metrics = 3;
diff --git a/tests/client_e2e/test_cottp_lwt_client_e2e.ml b/tests/client_e2e/test_cottp_lwt_client_e2e.ml
index b1ba3772..be63a959 100644
--- a/tests/client_e2e/test_cottp_lwt_client_e2e.ml
+++ b/tests/client_e2e/test_cottp_lwt_client_e2e.ml
@@ -26,6 +26,7 @@ let () =
           url;
           jobs = 1;
           procs = 1;
+          n_outer = 1;
           iterations = 1;
           batch_traces = 2;
           batch_metrics = 2;
@@ -36,6 +37,18 @@ let () =
           url;
           jobs = 3;
           procs = 1;
+          n_outer = 1;
+          iterations = 1;
+          batch_traces = 400;
+          batch_metrics = 3;
+          batch_logs = 400;
+        } );
+      ( "emit1_cohttp",
+        {
+          url;
+          jobs = 3;
+          procs = 1;
+          n_outer = 5;
           iterations = 1;
           batch_traces = 400;
           batch_metrics = 3;
diff --git a/tests/client_e2e/test_ocurl_client_e2e.ml b/tests/client_e2e/test_ocurl_client_e2e.ml
new file mode 100644
index 00000000..3f451a5d
--- /dev/null
+++ b/tests/client_e2e/test_ocurl_client_e2e.ml
@@ -0,0 +1,47 @@
+module Client = Opentelemetry_client
+module Proto = Opentelemetry.Proto
+open Clients_e2e_lib
+
+(* NOTE: This port must be different from that used by other integration tests,
+   to prevent socket binding clashes. *)
+let port = 4359
+
+let url = Printf.sprintf "http://localhost:%d" port
+
+let () =
+  Clients_e2e_lib.run_tests ~port
+    [
+      ( "emit1",
+        {
+          url;
+          jobs = 1;
+          procs = 1;
+          n_outer = 1;
+          iterations = 1;
+          batch_traces = 2;
+          batch_metrics = 2;
+          batch_logs = 2;
+        } );
+      ( "emit1",
+        {
+          url;
+          jobs = 3;
+          procs = 1;
+          n_outer = 1;
+          iterations = 1;
+          batch_traces = 400;
+          batch_metrics = 3;
+          batch_logs = 400;
+        } );
+      ( "emit1",
+        {
+          url;
+          jobs = 3;
+          procs = 1;
+          n_outer = 5;
+          iterations = 1;
+          batch_traces = 400;
+          batch_metrics = 3;
+          batch_logs = 400;
+        } );
+    ]
diff --git a/tests/logs/test_logs_e2e.ml b/tests/logs/test_logs_e2e.ml
index ed6a4fe3..a7a29af1 100644
--- a/tests/logs/test_logs_e2e.ml
+++ b/tests/logs/test_logs_e2e.ml
@@ -46,5 +46,7 @@ let tests (signal_batches : Client.Signal.t list) =
     signal_batches
 
 let () =
-  let signal_batches = Signal_gatherer.gather_signals ~port cmd in
+  let signal_batches =
+    Lwt_main.run (Signal_gatherer.gather_signals ~port cmd)
+  in
   tests signal_batches