Move brew cask --version into separate file.

Library/Homebrew/cask/lib/hbc/cli.rb

@@ -19,6 +19,7 @@ require "hbc/cli/reinstall"
 require "hbc/cli/search"
 require "hbc/cli/style"
 require "hbc/cli/uninstall"
+require "hbc/cli/--version"
 require "hbc/cli/zap"
 
 require "hbc/cli/internal_use_base"
@@ -116,7 +117,7 @@ module Hbc
       elsif command.to_s.include?("/") && require?(command.to_s)
         # external command as Ruby library with literal path, useful
         # for development and troubleshooting
-        sym = Pathname.new(command.to_s).basename(".rb").to_s.capitalize
+        sym = File.basename(command.to_s, ".rb").capitalize
         klass = begin
                   const_get(sym)
                 rescue NameError
@@ -247,16 +248,14 @@ module Hbc
         @attempted_verb = attempted_verb
       end
 
-      def run(*args)
-        if args.include?("--version") || @attempted_verb == "--version"
-          puts Hbc.full_version
-        else
+      def run(*_args)
         purpose
         usage
-          unless @attempted_verb.to_s.strip.empty? || @attempted_verb == "help"
-            raise CaskError, "Unknown command: #{@attempted_verb}"
-          end
-        end
+
+        return if @attempted_verb.to_s.strip.empty?
+        return if @attempted_verb == "help"
+
+        raise ArgumentError, "Unknown command: #{@attempted_verb}"
       end
 
       def purpose

Library/Homebrew/cask/lib/hbc/cli/--version.rb

@@ -0,0 +1,18 @@
+module Hbc
+  class CLI
+    class Version < Base
+      def self.command_name
+        "--#{super}"
+      end
+
+      def self.run(*args)
+        raise ArgumentError, "#{command_name} does not take arguments." unless args.empty?
+        puts Hbc.full_version
+      end
+
+      def self.help
+        "displays the Homebrew-Cask version"
+      end
+    end
+  end
+end

Library/Homebrew/test/cask/cli/--version_spec.rb

@@ -0,0 +1,13 @@
+describe Hbc::CLI::Version, :cask do
+  describe "::run" do
+    it "outputs the current Hombrew-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

Library/Homebrew/test/cask/cli/version_spec.rb

@@ -1,9 +0,0 @@
-describe "brew cask --version", :cask do
-  it "respects the --version argument" do
-    expect {
-      expect {
-        Hbc::CLI::NullCommand.new("--version").run
-      }.not_to output.to_stderr
-    }.to output(Hbc.full_version).to_stdout
-  end
-end

Library/Homebrew/test/cask/cli_spec.rb

@@ -27,8 +27,10 @@ describe Hbc::CLI, :cask do
     end
 
     it "passes `--version` along to the subcommand" do
-      expect(described_class).to receive(:run_command).with(noop_command, "--version")
-      described_class.process(%w[noop --version])
+      version_command = double("CLI::Version")
+      allow(described_class).to receive(:lookup_command).with("--version").and_return(version_command)
+      expect(described_class).to receive(:run_command).with(version_command)
+      described_class.process(["--version"])
     end
 
     it "prints help output when subcommand receives `--help` flag" do

Library/Homebrew/test/spec_helper.rb

@@ -112,4 +112,5 @@ RSpec.configure do |config|
   end
 end
 
+RSpec::Matchers.define_negated_matcher :not_to_output, :output
 RSpec::Matchers.alias_matcher :have_failed, :be_failed

Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb

@@ -1,6 +1,5 @@
 require "open3"
 
-RSpec::Matchers.define_negated_matcher :not_to_output, :output
 RSpec::Matchers.define_negated_matcher :be_a_failure, :be_a_success
 
 RSpec.shared_context "integration test" do