diff --git a/asynq.go b/asynq.go
index 90c6335..7d1b211 100644
--- a/asynq.go
+++ b/asynq.go
@@ -7,10 +7,8 @@ package asynq
 import (
 	"crypto/tls"
 	"fmt"
-	"time"
 
 	"github.com/go-redis/redis/v7"
-	"github.com/hibiken/asynq/internal/base"
 )
 
 // Task represents a unit of work to be performed.
@@ -32,28 +30,6 @@ func NewTask(typename string, payload map[string]interface{}) *Task {
 	}
 }
 
-// broker is a message broker that supports operations to manage task queues.
-//
-// See rdb.RDB as a reference implementation.
-type broker interface {
-	Enqueue(msg *base.TaskMessage) error
-	EnqueueUnique(msg *base.TaskMessage, ttl time.Duration) error
-	Dequeue(qnames ...string) (*base.TaskMessage, error)
-	Done(msg *base.TaskMessage) error
-	Requeue(msg *base.TaskMessage) error
-	Schedule(msg *base.TaskMessage, processAt time.Time) error
-	ScheduleUnique(msg *base.TaskMessage, processAt time.Time, ttl time.Duration) error
-	Retry(msg *base.TaskMessage, processAt time.Time, errMsg string) error
-	Kill(msg *base.TaskMessage, errMsg string) error
-	RequeueAll() (int64, error)
-	CheckAndEnqueue(qnames ...string) error
-	WriteServerState(ss *base.ServerState, ttl time.Duration) error
-	ClearServerState(ss *base.ServerState) error
-	CancelationPubSub() (*redis.PubSub, error) // TODO: Need to decouple from redis to support other brokers
-	PublishCancelation(id string) error
-	Close() error
-}
-
 // RedisConnOpt is a discriminated union of types that represent Redis connection configuration option.
 //
 // RedisConnOpt represents a sum of following types:
diff --git a/heartbeat.go b/heartbeat.go
index 06e0c02..b89845c 100644
--- a/heartbeat.go
+++ b/heartbeat.go
@@ -15,7 +15,7 @@ import (
 // indicate that the background worker process is up.
 type heartbeater struct {
 	logger Logger
-	broker broker
+	broker base.Broker
 
 	ss *base.ServerState
 
@@ -26,7 +26,7 @@ type heartbeater struct {
 	interval time.Duration
 }
 
-func newHeartbeater(l Logger, b broker, ss *base.ServerState, interval time.Duration) *heartbeater {
+func newHeartbeater(l Logger, b base.Broker, ss *base.ServerState, interval time.Duration) *heartbeater {
 	return &heartbeater{
 		logger:   l,
 		broker:   b,
diff --git a/internal/base/base.go b/internal/base/base.go
index 460d96a..ca71232 100644
--- a/internal/base/base.go
+++ b/internal/base/base.go
@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/go-redis/redis/v7"
 	"github.com/rs/xid"
 )
 
@@ -328,3 +329,25 @@ func (c *Cancelations) GetAll() []context.CancelFunc {
 	}
 	return res
 }
+
+// Broker is a message broker that supports operations to manage task queues.
+//
+// See rdb.RDB as a reference implementation.
+type Broker interface {
+	Enqueue(msg *TaskMessage) error
+	EnqueueUnique(msg *TaskMessage, ttl time.Duration) error
+	Dequeue(qnames ...string) (*TaskMessage, error)
+	Done(msg *TaskMessage) error
+	Requeue(msg *TaskMessage) error
+	Schedule(msg *TaskMessage, processAt time.Time) error
+	ScheduleUnique(msg *TaskMessage, processAt time.Time, ttl time.Duration) error
+	Retry(msg *TaskMessage, processAt time.Time, errMsg string) error
+	Kill(msg *TaskMessage, errMsg string) error
+	RequeueAll() (int64, error)
+	CheckAndEnqueue(qnames ...string) error
+	WriteServerState(ss *ServerState, ttl time.Duration) error
+	ClearServerState(ss *ServerState) error
+	CancelationPubSub() (*redis.PubSub, error) // TODO: Need to decouple from redis to support other brokers
+	PublishCancelation(id string) error
+	Close() error
+}
diff --git a/internal/testbroker/testbroker.go b/internal/testbroker/testbroker.go
index d06cd6a..0acab70 100644
--- a/internal/testbroker/testbroker.go
+++ b/internal/testbroker/testbroker.go
@@ -8,9 +8,10 @@ package testbroker
 import (
 	"errors"
 	"sync"
+	"time"
 
 	"github.com/go-redis/redis/v7"
-	"github.com/hibiken/asynq/internal/rdb"
+	"github.com/hibiken/asynq/internal/base"
 )
 
 var errRedisDown = errors.New("asynqtest: redis is down")
@@ -21,11 +22,12 @@ type TestBroker struct {
 	mu       sync.Mutex
 	sleeping bool
 
-	*rdb.RDB
+	// real broker
+	real base.Broker
 }
 
-func NewTestBroker(r *rdb.RDB) *TestBroker {
-	return &TestBroker{RDB: r}
+func NewTestBroker(b base.Broker) *TestBroker {
+	return &TestBroker{real: b}
 }
 
 func (tb *TestBroker) Sleep() {
@@ -40,11 +42,146 @@ func (tb *TestBroker) Wakeup() {
 	tb.sleeping = false
 }
 
+func (tb *TestBroker) Enqueue(msg *base.TaskMessage) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Enqueue(msg)
+}
+
+func (tb *TestBroker) EnqueueUnique(msg *base.TaskMessage, ttl time.Duration) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.EnqueueUnique(msg, ttl)
+}
+
+func (tb *TestBroker) Dequeue(qnames ...string) (*base.TaskMessage, error) {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return nil, errRedisDown
+	}
+	return tb.real.Dequeue(qnames...)
+}
+
+func (tb *TestBroker) Done(msg *base.TaskMessage) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Done(msg)
+}
+
+func (tb *TestBroker) Requeue(msg *base.TaskMessage) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Requeue(msg)
+}
+
+func (tb *TestBroker) Schedule(msg *base.TaskMessage, processAt time.Time) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Schedule(msg, processAt)
+}
+
+func (tb *TestBroker) ScheduleUnique(msg *base.TaskMessage, processAt time.Time, ttl time.Duration) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.ScheduleUnique(msg, processAt, ttl)
+}
+
+func (tb *TestBroker) Retry(msg *base.TaskMessage, processAt time.Time, errMsg string) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Retry(msg, processAt, errMsg)
+}
+
+func (tb *TestBroker) Kill(msg *base.TaskMessage, errMsg string) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Kill(msg, errMsg)
+}
+
+func (tb *TestBroker) RequeueAll() (int64, error) {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return 0, errRedisDown
+	}
+	return tb.real.RequeueAll()
+}
+
+func (tb *TestBroker) CheckAndEnqueue(qnames ...string) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.CheckAndEnqueue()
+}
+
+func (tb *TestBroker) WriteServerState(ss *base.ServerState, ttl time.Duration) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.WriteServerState(ss, ttl)
+}
+
+func (tb *TestBroker) ClearServerState(ss *base.ServerState) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.ClearServerState(ss)
+}
+
 func (tb *TestBroker) CancelationPubSub() (*redis.PubSub, error) {
 	tb.mu.Lock()
 	defer tb.mu.Unlock()
 	if tb.sleeping {
 		return nil, errRedisDown
 	}
-	return tb.RDB.CancelationPubSub()
+	return tb.real.CancelationPubSub()
+}
+
+func (tb *TestBroker) PublishCancelation(id string) error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.PublishCancelation(id)
+}
+
+func (tb *TestBroker) Close() error {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return errRedisDown
+	}
+	return tb.real.Close()
 }
diff --git a/processor.go b/processor.go
index baac355..adc7921 100644
--- a/processor.go
+++ b/processor.go
@@ -19,7 +19,7 @@ import (
 
 type processor struct {
 	logger Logger
-	broker broker
+	broker base.Broker
 
 	ss *base.ServerState
 
@@ -65,7 +65,7 @@ type retryDelayFunc func(n int, err error, task *Task) time.Duration
 
 type newProcessorParams struct {
 	logger          Logger
-	broker          broker
+	broker          base.Broker
 	ss              *base.ServerState
 	retryDelayFunc  retryDelayFunc
 	syncCh          chan<- *syncRequest
diff --git a/scheduler.go b/scheduler.go
index 6092d4a..8f4f860 100644
--- a/scheduler.go
+++ b/scheduler.go
@@ -7,11 +7,13 @@ package asynq
 import (
 	"sync"
 	"time"
+
+	"github.com/hibiken/asynq/internal/base"
 )
 
 type scheduler struct {
 	logger Logger
-	broker broker
+	broker base.Broker
 
 	// channel to communicate back to the long running "scheduler" goroutine.
 	done chan struct{}
@@ -23,7 +25,7 @@ type scheduler struct {
 	qnames []string
 }
 
-func newScheduler(l Logger, b broker, avgInterval time.Duration, qcfg map[string]int) *scheduler {
+func newScheduler(l Logger, b base.Broker, avgInterval time.Duration, qcfg map[string]int) *scheduler {
 	var qnames []string
 	for q := range qcfg {
 		qnames = append(qnames, q)
diff --git a/server.go b/server.go
index 9237116..9a10008 100644
--- a/server.go
+++ b/server.go
@@ -36,7 +36,7 @@ type Server struct {
 
 	logger Logger
 
-	broker broker
+	broker base.Broker
 
 	// wait group to wait for all goroutines to finish.
 	wg          sync.WaitGroup
diff --git a/subscriber.go b/subscriber.go
index f21bae5..c72ac89 100644
--- a/subscriber.go
+++ b/subscriber.go
@@ -14,7 +14,7 @@ import (
 
 type subscriber struct {
 	logger Logger
-	broker broker
+	broker base.Broker
 
 	// channel to communicate back to the long running "subscriber" goroutine.
 	done chan struct{}
@@ -26,7 +26,7 @@ type subscriber struct {
 	retryTimeout time.Duration
 }
 
-func newSubscriber(l Logger, b broker, cancelations *base.Cancelations) *subscriber {
+func newSubscriber(l Logger, b base.Broker, cancelations *base.Cancelations) *subscriber {
 	return &subscriber{
 		logger:       l,
 		broker:       b,