test: fix signed/unsigned comparison warnings

test/benchmark-fs-stat.c

@@ -45,7 +45,7 @@ struct async_req {
 
 static void warmup(const char* path) {
   uv_fs_t reqs[MAX_CONCURRENT_REQS];
-  int i;
+  unsigned int i;
 
   /* warm up the thread pool */
   for (i = 0; i < ARRAY_SIZE(reqs); i++)

test/benchmark-udp-pummel.c

@@ -143,13 +143,13 @@ static void timeout_cb(uv_timer_t* timer, int status) {
 }
 
 
-static int do_packet_storm(int n_senders,
-                           int n_receivers,
+static int do_packet_storm(unsigned int n_senders,
+                           unsigned int n_receivers,
                            unsigned long timeout) {
   uv_timer_t timer_handle;
   uint64_t duration;
   uv_loop_t* loop;
-  int i;
+  unsigned int i;
 
   ASSERT(n_senders <= ARRAY_SIZE(senders));
   ASSERT(n_receivers <= ARRAY_SIZE(receivers));

test/test-poll.c

@@ -205,7 +205,7 @@ static void destroy_connection_context(connection_context_t* context) {
 
 static void connection_poll_cb(uv_poll_t* handle, int status, int events) {
   connection_context_t* context = (connection_context_t*) handle->data;
-  int new_events;
+  unsigned int new_events;
   int r;
 
   ASSERT(status == 0);

test/test-stdio-over-pipes.c

@@ -196,7 +196,8 @@ int stdio_over_pipes_helper() {
 
   uv_write_t write_req[ARRAY_SIZE(buffers)];
   uv_buf_t buf[ARRAY_SIZE(buffers)];
-  int r, i;
+  unsigned int i;
+  int r;
   uv_loop_t* loop = uv_default_loop();
 
   ASSERT(UV_NAMED_PIPE == uv_guess_handle(0));

test/test-timer.c

@@ -90,7 +90,8 @@ TEST_IMPL(timer) {
   uv_timer_t once_timers[10];
   uv_timer_t *once;
   uv_timer_t repeat, never;
-  int i, r;
+  unsigned int i;
+  int r;
 
   start_time = uv_now(uv_default_loop());
   ASSERT(0 < start_time);