This is purely a style thing, but for tests without any assertions / expectations, I always find it a little confusing from a readability standpoint.

I know Ruby leans toward implicit everything for the sake of code brevity, but for someone new to the codebase (and Puppet in general), it's not totally clear what these 2 lines of code test.  

I would actually expect that `.retrieve` would return a `true` if this was a success.... and therefore your test is shorthand for 

```ruby
expect(resource.retrieve).to be_true
```

Yet the it statement reads `returns false when the check command returns zero`.  But the test returns `true`, and the `check` command is also being implicitly executed.