如何在Golang中对Google云存储进行单元测试？

Question

I'm writing an appengine app in Go that uses Google cloud storage.

For example, my "reading" code looks like:

client, err := storage.NewClient(ctx)
if err != nil {
    return nil, err
}
defer func() {
    if err := client.Close(); err != nil {
        panic(err)
    }
}()
r, err := client.Bucket(BucketName).Object(id).NewReader(ctx)
if err != nil {
    return nil, err
}
defer r.Close()
return ioutil.ReadAll(r)

... where ctx is a context from appengine.

When I run this code in a unit test (using aetest), it actually sends requests to my cloud storage; I'd like to run this hermetically instead, similar to how aetest allows fake datastore calls.

(Possibly related question, but it deals with python, and the linked github issue indicates it's solved in a python-specific way).

How can I do this?

Answer 1

Cloud Storage on the Python Development server is emulated using local files with the Blobstore service, which is why the solution of using a Blobstore stub with testbed (also Python-specific) worked. However there is no such local emulation for Cloud Storage on the Go runtime.

As Sachin suggested, the way to unit test Cloud Storage is to use a mock. This is the way it's done internally and on other runtimes, such as node.