Add --verbose-version (-V) flag

This addresses the second feature mentioned in standardrb#452. For context,
when debugging a RuboCop issue a user is asked to supply the
output of `rubocop -V`, and this streamlines this process for
standard users.

lib/standard/loads_runner.rb

@@ -1,9 +1,19 @@
+require_relative "runners/rubocop"
+require_relative "runners/version"
+require_relative "runners/verbose_version"
+require_relative "runners/help"
+
 module Standard
   class LoadsRunner
-    # Warning: clever metaprogramming. 99% of the time this is Runners::Rubocop
+    RUNNERS = {
+      rubocop: ::Standard::Runners::Rubocop,
+      version: ::Standard::Runners::Version,
+      verbose_version: ::Standard::Runners::VerboseVersion,
+      help: ::Standard::Runners::Help
+    }.freeze
+
     def call(command)
-      require_relative "runners/#{command}"
-      ::Standard::Runners.const_get(command.to_s.capitalize).new
+      RUNNERS[command].new
     end
   end
 end

lib/standard/merges_settings.rb

@@ -20,7 +20,7 @@ def call(argv, standard_yaml)
 
     def separate_argv(argv)
       argv.partition do |flag|
-        ["--generate-todo", "--fix", "--no-fix", "--version", "-v", "--help", "-h"].include?(flag)
+        ["--generate-todo", "--fix", "--no-fix", "--version", "-v", "--verbose-version", "-V", "--help", "-h"].include?(flag)
       end
     end
 
@@ -39,6 +39,8 @@ def determine_command(argv)
         :help
       elsif (argv & ["--version", "-v"]).any?
         :version
+      elsif (argv & ["--verbose-version", "-V"]).any?
+        :verbose_version
       elsif (argv & ["--generate-todo"]).any?
         :genignore
       else

lib/standard/runners/help.rb

@@ -9,13 +9,14 @@ def call(config)
 
           Options:
 
-            --fix             Automatically fix failures where possible
-            --no-fix          Do not automatically fix failures
-            --format <name>   Format output with any RuboCop formatter (e.g. "json")
-            --generate-todo   Create a .standard_todo.yml that lists all the files that contain errors
-            -v, --version     Print the version of Standard
-            -h, --help        Print this message
-            FILE              Files to lint [default: ./]
+            --fix                   Automatically fix failures where possible
+            --no-fix                Do not automatically fix failures
+            --format <name>         Format output with any RuboCop formatter (e.g. "json")
+            --generate-todo         Create a .standard_todo.yml that lists all the files that contain errors
+            -v, --version           Print the version of Standard
+            -V, --verbose-version   Print the version of Standard and its dependencies.
+            -h, --help              Print this message
+            FILE                    Files to lint [default: ./]
 
           Standard also forwards most CLI arguments to RuboCop. To see them, run:
 

lib/standard/runners/verbose_version.rb

@@ -0,0 +1,14 @@
+require_relative "rubocop"
+
+module Standard
+  module Runners
+    class VerboseVersion
+      def call(config)
+        puts <<-MSG.gsub(/^ {10}/, "")
+          Standard version: #{Standard::VERSION}
+          RuboCop version:  #{RuboCop::Version.version(debug: true)}
+        MSG
+      end
+    end
+  end
+end

test/standard/loads_runner_test.rb

@@ -17,6 +17,12 @@ def test_version
     assert_instance_of ::Standard::Runners::Version, result
   end
 
+  def test_verbose_version
+    result = @subject.call(:verbose_version)
+
+    assert_instance_of ::Standard::Runners::VerboseVersion, result
+  end
+
   def test_help
     result = @subject.call(:help)
 

test/standard/runners/help_test.rb

@@ -17,13 +17,14 @@ def test_prints_help
 
       Options:
 
-        --fix             Automatically fix failures where possible
-        --no-fix          Do not automatically fix failures
-        --format <name>   Format output with any RuboCop formatter (e.g. "json")
-        --generate-todo   Create a .standard_todo.yml that lists all the files that contain errors
-        -v, --version     Print the version of Standard
-        -h, --help        Print this message
-        FILE              Files to lint [default: ./]
+        --fix                   Automatically fix failures where possible
+        --no-fix                Do not automatically fix failures
+        --format <name>         Format output with any RuboCop formatter (e.g. "json")
+        --generate-todo         Create a .standard_todo.yml that lists all the files that contain errors
+        -v, --version           Print the version of Standard
+        -V, --verbose-version   Print the version of Standard and its dependencies.
+        -h, --help              Print this message
+        FILE                    Files to lint [default: ./]
 
       Standard also forwards most CLI arguments to RuboCop. To see them, run:
 

test/standard/runners/verbose_version_test.rb

@@ -0,0 +1,31 @@
+require_relative "../../test_helper"
+
+require "standard/runners/verbose_version"
+
+class Standard::Runners::VerboseVersionTest < UnitTest
+  def setup
+    @subject = Standard::Runners::VerboseVersion.new
+  end
+
+  def test_verbose_version
+    fake_out, _ = do_with_fake_io {
+      @subject.call(nil)
+    }
+
+    expect = <<-EXPECT.gsub(/^ {6}/, "")
+      Standard version: #{Standard::VERSION}
+      RuboCop version:  #{RuboCop::Version.version(debug: true)}
+    EXPECT
+
+    assert_equal expect, fake_out.string
+  end
+
+  def test_includes_rubocop_sub_dependencies
+    fake_out, _ = do_with_fake_io {
+      @subject.call(nil)
+    }
+
+    assert_match(/Parser/, fake_out.string)
+    assert_match(/rubocop-ast/, fake_out.string)
+  end
+end