* ADD [exchange_client] Add exchange client UT

Signed-off-by: Moi Ran <maoyi.ran@emqx.io>

src/mqtt/protocol/exchange/exchange_client_test.c

@@ -0,0 +1,50 @@
+#include "nng/nng.h"
+#include "core/nng_impl.h"
+#include "nng/exchange/exchange_client.h"
+#include "core/defs.h"
+#include <nuts.h>
+
+#define UNUSED(x) ((void) x)
+
+static int match_cb(void *msg)
+{
+	UNUSED(msg);
+	return 0;
+}
+
+static int target_cb(void *msg)
+{
+	UNUSED(msg);
+	return 0;
+}
+
+void test_exchange_client(void)
+{
+	nng_socket sock;
+	exchange_t *ex;
+	producer_t *p;
+
+	NUTS_TRUE(nng_exchange_client_open(&sock) == 0);
+
+	NUTS_TRUE(exchange_init(&ex, "exchange1") == 0);
+	NUTS_TRUE(ex != NULL);
+
+
+	NUTS_TRUE(producer_init(&p, match_cb, target_cb) == 0);
+	NUTS_TRUE(p != NULL);
+	NUTS_TRUE(exchange_add_prod(ex, p) == 0);
+
+	nng_socket_set_ptr(sock, NNG_OPT_EXCHANGE_ADD, ex);
+
+	int msg = 1;
+	nng_sendmsg(sock, (void *)&msg, NNG_FLAG_NONBLOCK);
+
+	nng_msleep(200);
+
+	return;
+}
+
+NUTS_TESTS = {
+	{ "Exchange client test", test_exchange_client },
+	{ NULL, NULL },
+};