Add test to simulate situation where redis is down

internal/testbroker/testbroker.go

@@ -0,0 +1,50 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+// Package testbroker exports a broker implementation that should be used in package testing.
+package testbroker
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/go-redis/redis/v7"
+	"github.com/hibiken/asynq/internal/rdb"
+)
+
+var errRedisDown = errors.New("asynqtest: redis is down")
+
+// TestBroker is a broker implementation which enables
+// to simulate Redis failure in tests.
+type TestBroker struct {
+	mu       sync.Mutex
+	sleeping bool
+
+	*rdb.RDB
+}
+
+func NewTestBroker(r *rdb.RDB) *TestBroker {
+	return &TestBroker{RDB: r}
+}
+
+func (tb *TestBroker) Sleep() {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	tb.sleeping = true
+}
+
+func (tb *TestBroker) Wakeup() {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	tb.sleeping = false
+}
+
+func (tb *TestBroker) CancelationPubSub() (*redis.PubSub, error) {
+	tb.mu.Lock()
+	defer tb.mu.Unlock()
+	if tb.sleeping {
+		return nil, errRedisDown
+	}
+	return tb.RDB.CancelationPubSub()
+}