test-throttle: use enum ThrottleDirection

Use enum ThrottleDirection instead in the throttle test codes.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20230728022006.1098509-3-pizhenwei@bytedance.com>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>

tests/unit/test-throttle.c

@@ -169,8 +169,8 @@ static void test_init(void)
 
     /* check initialized fields */
     g_assert(tt->clock_type == QEMU_CLOCK_VIRTUAL);
-    g_assert(tt->timers[0]);
-    g_assert(tt->timers[1]);
+    g_assert(tt->timers[THROTTLE_READ]);
+    g_assert(tt->timers[THROTTLE_WRITE]);
 
     /* check other fields where cleared */
     g_assert(!ts.previous_leak);
@@ -191,7 +191,7 @@ static void test_destroy(void)
     throttle_timers_init(tt, ctx, QEMU_CLOCK_VIRTUAL,
                          read_timer_cb, write_timer_cb, &ts);
     throttle_timers_destroy(tt);
-    for (i = 0; i < 2; i++) {
+    for (i = 0; i < THROTTLE_MAX; i++) {
         g_assert(!tt->timers[i]);
     }
 }