Added test setup document in README.md (#1585)

* Added test setup document in README.md

* Fixed typo

Author: jiekun

README.md

@@ -129,6 +129,27 @@ vals, err := rdb.Eval(ctx, "return {KEYS[1],ARGV[1]}", []string{"key"}, "hello")
 // custom command
 res, err := rdb.Do(ctx, "set", "key", "value").Result()
 ```
+## Run the test
+go-redis will start a redis-server and run the test cases. 
+
+The paths of redis-server bin file and redis config file are definded in `main_test.go`:
+```
+var (
+	redisServerBin, _  = filepath.Abs(filepath.Join("testdata", "redis", "src", "redis-server"))
+	redisServerConf, _ = filepath.Abs(filepath.Join("testdata", "redis", "redis.conf"))
+)
+```
+
+For local testing, you can change the variables to refer to your local files, or create a soft link to the corresponding folder for redis-server and copy the config file to `testdata/redis/`:
+```
+ln -s /usr/bin/redis-server ./go-redis/testdata/redis/src
+cp ./go-redis/testdata/redis.conf ./go-redis/testdata/redis/
+```
+
+Lastly, run:
+```
+go test
+```
 
 ## See also