I bumped with a problem of testing arguments of block calling in my rails project.

I've approximately this code (simplified):

```
DropboxApi.read_path do |batch|
    # some actions are here
end

```

Where batch is hash of data.

And i have an rspec spec which tests DropboxApi methods where i need to test some fields of 'batch'. I want to get something like this:

```
it { expect(batch).to respond_to(:data) }
it { expect(batch.data.count).to eq(6) }

```

I didn't find some ways to do it. Yield matchers are not helpful in that case, because they are checking only a block call and not it's arguments.

Could anybody help to implement what i want? I think i probably should change my approach for spec. But i don't know how yet.