diff --git a/.gitignore b/.gitignore
index 7058016a..af868454 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,6 +10,7 @@ tests/test_create
 tests/test_sleep
 tests/test_wait
 tests/test_io_new
+tests/test_client_server
 tests/test_cancel_sleep
 tests/test_cancel_sleep_2
 tests/test_cancel_connect
diff --git a/tests/makefile b/tests/makefile
index bec3b50b..759b01cc 100644
--- a/tests/makefile
+++ b/tests/makefile
@@ -9,6 +9,7 @@ TESTS      = test_new \
              test_sleep \
              test_wait \
              test_io_new \
+             test_client_server \
              test_cancel_sleep \
              test_cancel_sleep_2 \
              test_cancel_connect \
@@ -24,6 +25,8 @@ test_wait:
 	$(CC) $(CFLAGS) test_wait.c $(LFLAGS) -o test_wait
 test_io_new:
 	$(CC) $(CFLAGS) test_io_new.c $(LFLAGS) -o test_io_new
+test_client_server:
+	$(CC) $(CFLAGS) test_client_server.c $(LFLAGS) -o test_client_server
 test_cancel_sleep:
 	$(CC) $(CFLAGS) test_cancel_sleep.c $(LFLAGS) -o test_cancel_sleep
 test_cancel_sleep_2:
diff --git a/tests/test_client_server.c b/tests/test_client_server.c
new file mode 100644
index 00000000..de28bca2
--- /dev/null
+++ b/tests/test_client_server.c
@@ -0,0 +1,98 @@
+
+/*
+ * machinarium.
+ *
+ * Cooperative multitasking engine.
+*/
+
+#include <machinarium.h>
+#include <string.h>
+#include <assert.h>
+
+static void
+server(void *arg)
+{
+	printf("server: started\n");
+
+	mm_t env = arg;
+	mmio_t server = mm_io_new(env);
+
+	int rc;
+	rc = mm_bind(server, "127.0.0.1", 7778);
+	if (rc < 0) {
+		printf("server: bind failed\n");
+		mm_close(server);
+		return;
+	}
+
+	printf("server: waiting for connections (127.0.0.1:7778)\n");
+	mmio_t client;
+	rc = mm_accept(server, 16, &client);
+	if (rc < 0) {
+		printf("accept error.\n");
+		mm_close(server);
+		return;
+	}
+	char msg[] = "hello world";
+	rc = mm_write(client, msg, sizeof(msg), 0);
+	if (rc < 0) {
+		printf("server: write error.\n");
+		mm_close(client);
+		mm_close(server);
+		return;
+	}
+
+	mm_close(client);
+	mm_close(server);
+	printf("server: done\n");
+}
+
+static void
+client(void *arg)
+{
+	printf("client: started\n");
+
+	mm_t env = arg;
+	mmio_t client = mm_io_new(env);
+
+	int rc;
+	rc = mm_connect(client, "127.0.0.1", 7778, 0);
+	if (rc < 0) {
+		printf("client: connect failed\n");
+		mm_close(client);
+		return;
+	}
+
+	printf("client: connected\n");
+
+	rc = mm_read(client, 12, 0);
+	if (rc < 0) {
+		printf("client: read failed\n");
+		mm_close(client);
+		return;
+	}
+
+	char *buf = mm_read_buf(client);
+	assert(memcmp(buf, "hello world", 12) == 0);
+
+	rc = mm_read(client, 1, 0);
+	if (rc < 0) {
+		/* eof */
+	}
+
+	mm_close(client);
+
+	printf("client: done\n");
+	mm_stop(env);
+}
+
+int
+main(int argc, char *argv[])
+{
+	mm_t env = mm_new();
+	mm_create(env, server, env);
+	mm_create(env, client, env);
+	mm_start(env);
+	mm_free(env);
+	return 0;
+}