You may be able to just stub this value like:

```ruby
before { Chef::Config.stub(:[]).with(:diff_disabled).and_return(true) }
```

This may save you from having to capture `@original_diff_disable`. I would also consider DRYing things up with an RSpec shared context which contains the `before` and `after` blocks:

```ruby
include_context "file diff disabled"
```