Mocking redis server with miniredis fails

Question

Golang newbie here :)
I have a redis client wrapper over go-redis and I want to test that it works properly. I have tried using miniredis to mock the redis server I would be connecting to, but I keep getting an error.

When I have everything in the same function then this works - I am able to run go-redis against the miniredis service. However, when I try to use my client it fails.
I've tried looking in the docs of go-redis and miniredis but couldn't find any answers. I've also tried having the miniredis server defined as a global variable but that didn't help as well.

client impl:

package redis

import (
    "errors"
    "fmt"
    "github.com/go-redis/redis"
    "go.uber.org/zap"
    "os"
    "strconv"
    "time"
)

var redisClient *redis.Client
var redisCert string

var redisURL = "localhost:6379"
var redisPass = ""
var redisDB = 0

type Client struct {
    redisClient *redis.Client
}
func newRedisClient() *Client {
    if os.Getenv("REDIS_URL") != "" {
        redisURL = os.Getenv("REDIS_URL")
    }
    if os.Getenv("REDIS_PASS") != "" {
        redisPass = os.Getenv("REDIS_PASS")
    }
    if os.Getenv("REDIS_DB") != "" {
        redisDB, _ = strconv.Atoi(os.Getenv("REDIS_DB"))
    }

    client := redis.NewClient(&redis.Options{
        Addr:      redisURL,
        Password:  redisPass,
        DB:        redisDB,
    })
    redisClient = client
    _, err := redisClient.Ping().Result()
    if err != nil {
        fmt.Println("Failed to connect", zap.Error(err))
        return nil
    }
    fmt.Println("Redis client is ready")
    return &Client{redisClient: client}
}

func (r *Client) Get(key string) (string, error) {
    res, err := redisClient.Get(key).Result()
    fmt.Println(res, err)
    if err == redis.Nil {
        return "", errors.New("Key Not Found")
    } else if err != nil {
        return "", err
    } else {
        return res, nil
    }

}

Test impl:

package redis

import (
    "github.com/alicebob/miniredis/v2"
    "gopkg.in/go-playground/assert.v1"
    "os"
    "testing"
)

var mr *miniredis.Miniredis

func TestGet(t *testing.T) {
    mr, _ = miniredis.Run()
    mr.Set("test1", "some")
    os.Setenv("REDIS_URL", mr.Addr())
    c := newRedisClient()
    r, err := c.Get("test1")
    assert.Equal(t, r, "")
    assert.Equal(t, err, "")
    mr.Close()
}

What am I doing wrong?

Answer 1

Mock failed through miniredis, you can use SetError: https://github.com/alicebob/miniredis/issues/36#issuecomment-642009898

func TestGet(t *testing.T) {
    mr, _ = miniredis.Run()

    // normal test
    // ...

    // error test
    mr.SetError("mock error")
    _, err = c.Get("test2")
    assert.EqualError(t, err, "mock error")

    mr.Close()
}