Given that `expect { }.not_to raise_error` doesn't actually add any new assertions (if the block raised an error, the example would fail anyway), I tend to only use it as a contrast to another expectation of `expect {}.to raise_error` particularly if the method-under-test's purpose is to raise-or-no-op.

Here `reset` does something very specific, and it would be good to test that, with something like this:

``` ruby
dbl = double(:foo => "bar")
expect {
  reset dbl
}.to change { dbl.respond_to?(:foo) }.from(true).to(false)
```

Thoughts?