Stubbing S3 presigned_url in AWS SDK v2

Question

I'm attempting to use the AWS Ruby SDK response stubs to test some error handling in my interactions with S3.

I've been able to stub a simplistic put_object case, but for some reason I cannot stub presigned_url . It's important to note that I am using an older version of the SDK.

# Gemfile
gem 'aws-sdk', '2.3.22'

describe 'Stubbing AWS' do
  module S3Helper
    def self.presigned_url(object_key:, client:)
      resource = ::Aws::S3::Resource.new(:client => client)
      bucket = resource.bucket('my-great-bucket')
      bucket
        .object(object_key)
        .presigned_url(:get)
    end
  end

  it 'should allow me to stub signed_url' do
    test_client = Aws::S3::Client.new(
      :access_key_id => ENV['SECRET_ACCESS_KEY_ID'],
      :secret_access_key => ENV['SECRET_ACCESS_KEY'],
      :region => ENV['AWS_REGION']
    )

    test_client.stub_responses(:get_object 'NotFound')

    expect do
      S3Helper.presigned_url(
        object_key: 'my-key',
        client: client
      )
    end.to raise(/NotFound/)
  end
end

The test fails because the response does not trigger the NotFound error, even though I can clearly see that a get_object request was made (and a fake response was returned) in the application logs.

I'm currently solving around this by passing a mock client to my service, and stubbing out the object and presigned_url methods, but I'd prefer to have the SDK do the mocking for me. What am I missing?

Answer 1

I think you are not stubbing the response correctly.

Try this way:

test_client.stub_responses(:get_object, 'NotFound')

From the documentation, I see that the stub_responses method accepts an array of arguments, not a hash.