go - 如何在 golang 中模拟 GCP 的存储？

Question

我真的不熟悉在 go 中模拟第三方库，我现在正在模拟 cloud.google.com/go/storage

我正在使用 mockery .这是我当前的界面:

//Client storage client
type Client interface {
    Bucket(name string) BucketHandle
    Buckets(ctx context.Context, projectID string) BucketIterator
}

//BucketHandle storage's BucketHandle
type BucketHandle interface {
    Attrs(context.Context) (*storage.BucketAttrs, error)
    Objects(context.Context, *storage.Query) ObjectIterator
}

//ObjectIterator storage's ObjectIterator
type ObjectIterator interface {
    Next() (*storage.ObjectAttrs, error)
}

//BucketIterator storage's BucketIterator
type BucketIterator interface {
    Next() (*storage.BucketAttrs, error)
}

这就是我在我的函数中使用它的方式

//Runner runner for this module
type Runner struct {
    StorageClient stiface.Client
}

.... function
   //get storage client
    client, err := storage.NewClient(ctx)
    if err != nil {
        return err
    }

    runner := Runner{
        StorageClient: client,
    }
.... rest of functions

但是，我得到了这个错误:

cannot use client (type *"cloud.google.com/go/storage".Client) as type stiface.Client in field value: *"cloud.google.com/go/storage".Client does not implement stiface.Client (wrong type for Bucket method) have Bucket(string) *"cloud.google.com/go/storage".BucketHandle want Bucket(string) stiface.BucketHandle

我做错了什么？谢谢!

编辑

这是我要模拟的代码示例之一。我想模拟 bucketIterator.Next():

//GetBuckets get list of buckets
func GetBuckets(ctx context.Context, client *storage.Client, projectName string) []checker.Resource {
    //Get bucket iterator based on a project
    bucketIterator := client.Buckets(ctx, projectName)
    //iterate over the buckets and store bucket details
    buckets := make([]checker.Resource, 0)
    for bucket, done := bucketIterator.Next(); done == nil; bucket, done = bucketIterator.Next() {
        buckets = append(buckets, checker.Resource{
            Name: bucket.Name,
            Type: "Bucket",
        })
    }
    return buckets
}

Answer 1

错误消息基本上是说您的 stiface.Client 定义了 *storage.Client 未实现的接口(interface)。乍一看，您的代码看起来是有效的，但问题在于您的接口(interface)方法签名，因为它们将输出作为接口(interface)。

Go 对语句进行了区分:

• 这个函数返回一个BucketHandle
• 并且此函数返回一个 *storage.BucketHandle，它是一个 BucketHandle

尝试更改您的接口(interface)以返回 *storage.BucketHandle。您可以在 mockery S3API example 中看到类似行为的更复杂示例。其中函数返回 s3 类型，而不是它们自己的接口(interface)。