vendor/github.com/docker/distribution/registry/storage/cache/redis/redis_test.go

package redis

import (
	"flag"
	"os"
	"testing"
	"time"

	"github.com/docker/distribution/registry/storage/cache/cachecheck"
	"github.com/garyburd/redigo/redis"
)

var redisAddr string

func init() {
	flag.StringVar(&redisAddr, "test.registry.storage.cache.redis.addr", "", "configure the address of a test instance of redis")
}

// TestRedisLayerInfoCache exercises a live redis instance using the cache
// implementation.
func TestRedisBlobDescriptorCacheProvider(t *testing.T) {
	if redisAddr == "" {
		// fallback to an environement variable
		redisAddr = os.Getenv("TEST_REGISTRY_STORAGE_CACHE_REDIS_ADDR")
	}

	if redisAddr == "" {
		// skip if still not set
		t.Skip("please set -test.registry.storage.cache.redis.addr to test layer info cache against redis")
	}

	pool := &redis.Pool{
		Dial: func() (redis.Conn, error) {
			return redis.Dial("tcp", redisAddr)
		},
		MaxIdle:   1,
		MaxActive: 2,
		TestOnBorrow: func(c redis.Conn, t time.Time) error {
			_, err := c.Do("PING")
			return err
		},
		Wait: false, // if a connection is not available, proceed without cache.
	}

	// Clear the database
	conn := pool.Get()
	if _, err := conn.Do("FLUSHDB"); err != nil {
		t.Fatalf("unexpected error flushing redis db: %v", err)
	}
	conn.Close()

	cachecheck.CheckBlobDescriptorCache(t, NewRedisBlobDescriptorCacheProvider(pool))
}