If command line 'host' query works should host resource be_resolvable?

I’d like to use the host resource is_resolvable matcher on a host in my local domain:

describe host("foo.mydomain") do
  it { should be_resolvable }

I can see the host and resolve it’s IP address from the command line (OS/X) with “host”:

$ host -t A foo.mydomain
foo.mydomain has address

However the matcher always fails. I suspect I’ve misunderstood something about how inspec finds local utilities like ‘host’ or ‘dig’ to use. Or am I going about this in the wrong way?

Any advice much appreciated,