Fix rate limiter and add test.

rate_limit_test.go

@@ -0,0 +1,28 @@
+package redis
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestRateLimiter(t *testing.T) {
+	const n = 100000
+	rl := newRateLimiter(time.Second, n)
+
+	wg := &sync.WaitGroup{}
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func() {
+			if !rl.Check() {
+				panic("check failed")
+			}
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+
+	if rl.Check() && rl.Check() {
+		t.Fatal("check passed")
+	}
+}