describe Hbc::CLI::Version, :cask do describe "::run" do it "outputs the current Homebrew-Cask version" do expect { described_class.run } .to output(/\AHomebrew-Cask.*\d+\.\d+\.\d+/).to_stdout .and not_to_output.to_stderr end it "does not support arguments" do expect { described_class.run(:foo, :bar) }.to raise_error(ArgumentError) end end end