Add tests to simulate cases where server cannot talk to redis

server_test.go

@@ -6,10 +6,13 @@ package asynq
 
 import (
 	"context"
+	"fmt"
 	"syscall"
 	"testing"
 	"time"
 
+	"github.com/hibiken/asynq/internal/rdb"
+	"github.com/hibiken/asynq/internal/testbroker"
 	"go.uber.org/goleak"
 )
 
@@ -113,3 +116,95 @@ func TestServerErrServerRunning(t *testing.T) {
 	}
 	srv.Stop()
 }
+
+func TestServerWithRedisDown(t *testing.T) {
+	// Make sure that server does not panic and exit if redis is down.
+	defer func() {
+		if r := recover(); r != nil {
+			t.Errorf("panic occurred: %v", r)
+		}
+	}()
+	r := rdb.NewRDB(setup(t))
+	testBroker := testbroker.NewTestBroker(r)
+	srv := NewServer(RedisClientOpt{Addr: ":6379"}, Config{})
+	srv.broker = testBroker
+	srv.scheduler.broker = testBroker
+	srv.heartbeater.broker = testBroker
+	srv.processor.broker = testBroker
+	srv.subscriber.broker = testBroker
+	testBroker.Sleep()
+
+	// no-op handler
+	h := func(ctx context.Context, task *Task) error {
+		return nil
+	}
+
+	err := srv.Start(HandlerFunc(h))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	time.Sleep(3 * time.Second)
+
+	srv.Stop()
+}
+
+func TestServerWithFlakyBroker(t *testing.T) {
+	// Make sure that server does not panic and exit if redis is down.
+	defer func() {
+		if r := recover(); r != nil {
+			t.Errorf("panic occurred: %v", r)
+		}
+	}()
+	r := rdb.NewRDB(setup(t))
+	testBroker := testbroker.NewTestBroker(r)
+	srv := NewServer(RedisClientOpt{Addr: redisAddr, DB: redisDB}, Config{})
+	srv.broker = testBroker
+	srv.scheduler.broker = testBroker
+	srv.heartbeater.broker = testBroker
+	srv.processor.broker = testBroker
+	srv.subscriber.broker = testBroker
+
+	c := NewClient(RedisClientOpt{Addr: redisAddr, DB: redisDB})
+
+	h := func(ctx context.Context, task *Task) error {
+		// force task retry.
+		if task.Type == "bad_task" {
+			return fmt.Errorf("could not process %q", task.Type)
+		}
+		time.Sleep(2 * time.Second)
+		return nil
+	}
+
+	err := srv.Start(HandlerFunc(h))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i := 0; i < 10; i++ {
+		err := c.Enqueue(NewTask("enqueued", nil), MaxRetry(i))
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = c.Enqueue(NewTask("bad_task", nil))
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = c.EnqueueIn(time.Duration(i)*time.Second, NewTask("scheduled", nil))
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// simulate redis going down.
+	testBroker.Sleep()
+
+	time.Sleep(3 * time.Second)
+
+	// simulate redis comes back online.
+	testBroker.Wakeup()
+
+	time.Sleep(3 * time.Second)
+
+	srv.Stop()
+}