Mocking JSONSet

[jaysonhurd]

Hi - I'm using redismock for unit testing. I am not able to get the JSONSet mocked. Tried ExpectHMSet, ExpectSet etc. but no dice. Has anyone done this?

[ljluestc]

package redismockexample

import (
    "context"
    "encoding/json"
    "errors"
    "testing"
    "time"

    "github.com/redis/go-redis/v9"
    "github.com/go-redis/redismock/v9"
    "github.com/stretchr/testify/assert"
)

// User represents a user profile stored as JSON in Redis.
type User struct {
    ID   string `json:"id"`
    Name string `json:"name"`
    Age  int    `json:"age"`
}

// StoreUserProfile stores a user profile as JSON in Redis using JSON.SET.
func StoreUserProfile(ctx context.Context, client *redis.Client, key string, user User) error {
    // Serialize user to JSON
    userJSON, err := json.Marshal(user)
    if err != nil {
        return err
    }

    // Use JSON.SET to store the JSON at the root path (.)
    // Note: JSONSet is a convenience method in go-redis/v9 for Redis JSON
    cmd := client.JSONSet(ctx, key, ".", string(userJSON))
    if err := cmd.Err(); err != nil {
        return err
    }

    return nil
}

// TestStoreUserProfile tests the StoreUserProfile function with mocked JSON.SET.
func TestStoreUserProfile(t *testing.T) {
    ctx := context.Background()

    // Create a mock Redis client
    db, mock := redismock.NewClientMock()

    // Test case 1: Successful JSON.SET
    t.Run("Successful JSON.SET", func(t *testing.T) {
        // Sample user
        user := User{ID: "123", Name: "Alice", Age: 30}
        key := "user:123"
        userJSON, _ := json.Marshal(user)

        // Mock JSON.SET
        // JSON.SET is sent as a raw command: JSON.SET <key> <path> <value>
        mock.ExpectDo("JSON.SET", key, ".", string(userJSON)).SetVal("OK")

        // Call the function
        err := StoreUserProfile(ctx, db, key, user)

        // Assert results
        assert.NoError(t, err)
        assert.NoError(t, mock.ExpectationsWereMet())
    })

    // Test case 2: JSON.SET fails with error
    t.Run("Failed JSON.SET", func(t *testing.T) {
        // Sample user
        user := User{ID: "456", Name: "Bob", Age: 25}
        key := "user:456"
        userJSON, _ := json.Marshal(user)

        // Mock JSON.SET to return an error
        mock.ExpectDo("JSON.SET", key, ".", string(userJSON)).SetErr(errors.New("Redis JSON module not available"))

        // Call the function
        err := StoreUserProfile(ctx, db, key, user)

        // Assert results
        assert.Error(t, err)
        assert.Contains(t, err.Error(), "Redis JSON module not available")
        assert.NoError(t, mock.ExpectationsWereMet())
    })

    // Test case 3: Invalid JSON
    t.Run("Invalid JSON", func(t *testing.T) {
        // Create a user with invalid JSON (e.g., unexported fields cause empty JSON)
        type invalidUser struct {
            id string // unexported field
        }
        user := invalidUser{id: "789"}
        key := "user:789"

        // No need to mock JSON.SET since JSON marshaling will fail
        err := StoreUserProfile(ctx, db, key, user)

        // Assert results
        assert.Error(t, err)
        assert.Contains(t, err.Error(), "json: error calling MarshalJSON")
        assert.NoError(t, mock.ExpectationsWereMet())
    })
}