Fix rate limiter and add test.

Makefile

@@ -1,2 +1,2 @@
 all:
-	go test gopkg.in/redis.v2
+	go test gopkg.in/redis.v2 -cpu=1,2,4

commands.go

@@ -1,6 +1,7 @@
 package redis
 
 import (
+	"io"
 	"strconv"
 	"time"
 )
@@ -1120,7 +1121,16 @@ func (c *Client) shutdown(modifier string) *StatusCmd {
 	}
 	cmd := NewStatusCmd(args...)
 	c.Process(cmd)
-	c.Close()
+	if err := cmd.Err(); err != nil {
+		if err == io.EOF {
+			// Server quit as expected.
+			cmd.err = nil
+		}
+	} else {
+		// Server did not quit. String reply contains the reason.
+		cmd.err = errorf(cmd.val)
+		cmd.val = ""
+	}
 	return cmd
 }
 

rate_limit.go

@@ -37,10 +37,11 @@ func (rl *rateLimiter) Check() bool {
 			if atomic.CompareAndSwapInt64(&rl.v, v, v-1) {
 				return true
 			}
-		}
+		} else {
 			return false
 		}
 	}
+}
 
 func (rl *rateLimiter) Close() error {
 	atomic.StoreInt64(&rl._closed, 1)

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")
+	}
+}

sentinel_test.go

@@ -88,10 +88,13 @@ func TestSentinel(t *testing.T) {
 	slavePort := "8124"
 	sentinelPort := "8125"
 
-	_, err := startRedis(masterPort)
+	masterCmd, err := startRedis(masterPort)
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer masterCmd.Process.Kill()
+
+	// Wait for master to start.
 	time.Sleep(200 * time.Millisecond)
 
 	master := redis.NewTCPClient(&redis.Options{
@@ -100,12 +103,14 @@ func TestSentinel(t *testing.T) {
 	if err := master.Ping().Err(); err != nil {
 		t.Fatal(err)
 	}
-	defer master.Shutdown()
 
-	_, err = startRedisSlave(slavePort, masterPort)
+	slaveCmd, err := startRedisSlave(slavePort, masterPort)
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer slaveCmd.Process.Kill()
+
+	// Wait for slave to start.
 	time.Sleep(200 * time.Millisecond)
 
 	slave := redis.NewTCPClient(&redis.Options{
@@ -114,12 +119,14 @@ func TestSentinel(t *testing.T) {
 	if err := slave.Ping().Err(); err != nil {
 		t.Fatal(err)
 	}
-	defer slave.Shutdown()
 
-	_, err = startRedisSentinel(sentinelPort, masterName, masterPort)
+	sentinelCmd, err := startRedisSentinel(sentinelPort, masterName, masterPort)
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer sentinelCmd.Process.Kill()
+
+	// Wait for sentinel to start.
 	time.Sleep(200 * time.Millisecond)
 
 	sentinel := redis.NewTCPClient(&redis.Options{
@@ -147,8 +154,13 @@ func TestSentinel(t *testing.T) {
 		t.Fatalf(`got %q, expected "master"`, val)
 	}
 
-	// Kill master.
-	master.Shutdown()
+	// Kill Redis master.
+	if err := masterCmd.Process.Kill(); err != nil {
+		t.Fatal(err)
+	}
+	if err := master.Ping().Err(); err == nil {
+		t.Fatalf("master was not killed")
+	}
 
 	// Wait for Redis sentinel to elect new master.
 	time.Sleep(5 * time.Second)