Add RuboCop

.rubocop.yml

+AllCops:
+  TargetRubyVersion: 2.2
+  DisplayCopNames: true
+
+#
+# Layout
+#
+
+Layout/IndentHeredoc:
+  Enabled: false
+
+#
+# Metrics
+#
+
+Metrics/AbcSize:
+  Enabled: false
+
+Metrics/CyclomaticComplexity:
+  Enabled: false
+
+Metrics/PerceivedComplexity:
+  Enabled: false
+
+Metrics/BlockLength:
+  Max: 100
+
+Metrics/ClassLength:
+  Max: 100
+
+Metrics/LineLength:
+  Max: 128
+
+Metrics/MethodLength:
+  Max: 25
+
+#
+# Style
+#
+
+Style/FrozenStringLiteralComment:
+  Enabled: true
+
+Style/StringLiterals:
+  EnforcedStyle: double_quotes

Gemfile

@@ -8,5 +8,6 @@ group :development, :test do
   gem "rake", ">= 10"
   gem "rake-compiler", "~> 1.0"
   gem "rake-compiler-dock", "~> 0.6"
-  gem "rspec", "~> 3"
+  gem "rspec", "~> 3.7"
+  gem "rubocop", "0.52.1"
 end

Rakefile

 require "bundler/gem_tasks"
 require "rspec/core/rake_task"
-require 'rake/extensiontask'
+require "rake/extensiontask"
 
 RSpec::Core::RakeTask.new
 
-task default: :spec
+require "rubocop/rake_task"
+RuboCop::RakeTask.new
 
-MAKE = ENV['MAKE'] || ENV['make'] || "make"
-RUBY_CC_VERSION = ENV['RUBY_CC_VERSION'] || '2.3.0'
+task default: %w[spec rubocop]
+
+MAKE = ENV["MAKE"] || ENV["make"] || "make"
+RUBY_CC_VERSION = ENV["RUBY_CC_VERSION"] || "2.3.0"
 
 desc "Build Windows binary packages"
-task 'gem:windows' do
-  require 'rake_compiler_dock'
-  if File.exist? "vendor/libsodium/Makefile"
-    RakeCompilerDock.sh "cd vendor/libsodium && #{MAKE} clean"
-  end
-  sh "bundle package"   # Avoid repeated downloads of gems by using gem files from the host.
+task "gem:windows" do
+  require "rake_compiler_dock"
+  RakeCompilerDock.sh "cd vendor/libsodium && #{MAKE} clean" if File.exist? "vendor/libsodium/Makefile"
+  sh "bundle package" # Avoid repeated downloads of gems by using gem files from the host.
   RakeCompilerDock.sh "bundle --local && RUBY_CC_VERSION=#{RUBY_CC_VERSION} rake cross native gem"
 end
 
 spec = Gem::Specification.load("rbnacl-libsodium.gemspec")
 
-PLATFORMS = ['x86-mingw32', 'x64-mingw32']
+PLATFORMS = ["x86-mingw32", "x64-mingw32"].freeze
 Rake::ExtensionTask.new("fake_ext", spec) do |ext|
-  ext.ext_dir = 'ext/rbnacl'
+  ext.ext_dir = "ext/rbnacl"
   ext.cross_compile = true
   ext.cross_platform = PLATFORMS
   ext.cross_config_options << {
-    'x86-mingw32' => '--with-host=i686-w64-mingw32',
-    'x64-mingw32' => '--with-host=x86_64-w64-mingw32'
+    "x86-mingw32" => "--with-host=i686-w64-mingw32",
+    "x64-mingw32" => "--with-host=x86_64-w64-mingw32"
   }
   ext.cross_compiling do |gem_spec|
-    gem_spec.files.reject! { |f| /lib\/fake_ext\.so\Z/ =~ f }
+    gem_spec.files.reject! { |f| %r{lib\/fake_ext\.so\Z} =~ f }
     stage_path = "#{ext.tmp_dir}/#{gem_spec.platform}/stage"
     gem_spec.files += Dir["#{stage_path}/vendor/libsodium/dist/**/*"].map do |stage|
       gem_path = stage.sub(stage_path + "/", "")
@@ -46,7 +47,5 @@ end
 
 PLATFORMS.each do |platf|
   copy_task = "copy:fake_ext:#{platf}:#{RUBY_CC_VERSION}"
-  if Rake::Task.task_defined?(copy_task)
-    Rake::Task[copy_task].clear_actions
-  end
+  Rake::Task[copy_task].clear_actions if Rake::Task.task_defined?(copy_task)
 end

ext/rbnacl/extconf.rb

-require 'mkmf'
+# frozen_string_literal: true
+
+require "mkmf"
 
 def sys(cmd)
   puts " -- #{cmd}"
-  unless ret = system(cmd)
-    raise "ERROR: '#{cmd}' failed"
-  end
+  ret = system(cmd)
+  raise "ERROR: '#{cmd}' failed" unless ret
   ret
 end
 
@@ -17,20 +18,18 @@ clean:
 MAKEFILE
 
 HOST = arg_config("--host")
-OPTIONS = []
-if HOST
-  OPTIONS << "--host=#{HOST}"
-end
+OPTIONS = [].freeze
+OPTIONS << "--host=#{HOST}" if HOST
 
-CWD = File.expand_path(File.dirname(__FILE__))
-LIBSODIUM_DIR = File.expand_path(File.join(CWD, '..', '..', 'vendor', 'libsodium'))
-MAKE = ENV['MAKE'] || ENV['make'] || "make"
-if HOST
-  # install to the stage directory for rake-compiler
-  DIST = File.expand_path(File.join(CWD, '..', '..', 'tmp', RUBY_PLATFORM, 'stage', 'vendor', 'libsodium', 'dist'))
-else
-  DIST = "#{LIBSODIUM_DIR}/dist"
-end
+CWD = __dir__
+LIBSODIUM_DIR = File.expand_path(File.join(CWD, "..", "..", "vendor", "libsodium"))
+MAKE = ENV["MAKE"] || ENV["make"] || "make"
+DIST = if HOST
+         # install to the stage directory for rake-compiler
+         File.expand_path(File.join(CWD, "..", "..", "tmp", RUBY_PLATFORM, "stage", "vendor", "libsodium", "dist"))
+       else
+         "#{LIBSODIUM_DIR}/dist".freeze
+       end
 
 Dir.chdir(LIBSODIUM_DIR) do
   # sh is required to run configure on Windows

lib/rbnacl/libsodium.rb

-require 'rbnacl/libsodium/version'
+require "rbnacl/libsodium/version"
 
 module RbNaCl
+  # Installer for the libsodium native library
   module Libsodium
     class << self
       def sodiumlib_dir
-        sodiumlib32_dir = File.expand_path('../../../vendor/libsodium/dist/lib/', __FILE__)
-        sodiumlib64_dir = File.expand_path('../../../vendor/libsodium/dist/lib64/', __FILE__)
+        sodiumlib32_dir = File.expand_path("../../../vendor/libsodium/dist/lib/", __FILE__)
+        sodiumlib64_dir = File.expand_path("../../../vendor/libsodium/dist/lib64/", __FILE__)
         [sodiumlib32_dir, sodiumlib64_dir].select { |dir| Dir.exist?(dir) }.first
       end
 
       def sodiumlib_glob
         case RUBY_DESCRIPTION
-        when /darwin/ then 'libsodium*.dylib'
-        when /Windows|(win|mingw)32/ then '../bin/libsodium*.dll'
-        when /openbsd/ then 'libsodium*.so.*'
-        else 'libsodium*.so'
+        when /darwin/ then "libsodium*.dylib"
+        when /Windows|(win|mingw)32/ then "../bin/libsodium*.dll"
+        when /openbsd/ then "libsodium*.so.*"
+        else "libsodium*.so"
         end
       end
     end
@@ -23,4 +24,4 @@ module RbNaCl
   end
 end
 
-require 'rbnacl'
+require "rbnacl"

lib/rbnacl/libsodium/version.rb

+# frozen_string_literal: true
+
 module RbNaCl
   module Libsodium
-    VERSION = '1.0.16'
+    VERSION = "1.0.16".freeze
   end
 end

rbnacl-libsodium.gemspec

-# coding: utf-8
-lib = File.expand_path('../lib', __FILE__)
+# frozen_string_literal: true
+
+lib = File.expand_path("../lib", __FILE__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
-require 'rbnacl/libsodium/version'
+require "rbnacl/libsodium/version"
 
 Gem::Specification.new do |spec|
   spec.name          = "rbnacl-libsodium"
   spec.version       = RbNaCl::Libsodium::VERSION
   spec.authors       = ["Artiom Di", "Tony Arcieri"]
-  spec.date          = Time.now.strftime('%Y-%m-%d')
   spec.email         = ["kron82@gmail.com", "bascule@gmail.com"]
-  spec.summary       = %q{rbnacl with bundled libsodium}
-  spec.homepage      = "https://github.com/crypto-rb/rbnacl-libsodium"
+  spec.summary       = "rbnacl with bundled libsodium"
+  spec.homepage      = "https://github.com/cryptosphere/rbnacl-libsodium"
   spec.license       = "MIT"
-
-  spec.files         = `git ls-files -z`.split("\x0")
-  spec.files         += Dir.glob("vendor/libsodium/**/*")
+  spec.files         = `git ls-files -z`.split("\x0") + Dir.glob("vendor/libsodium/**/*")
   spec.require_paths = ["lib"]
+  spec.extensions    = ["ext/rbnacl/extconf.rb"]
 
-  spec.extensions    = ['ext/rbnacl/extconf.rb']
-
+  spec.required_ruby_version = ">= 2.2.6"
   spec.add_runtime_dependency "rbnacl", ">= 5.0.0"
-  spec.required_ruby_version = '>= 2.2.6'
-
   spec.add_development_dependency "bundler", "~> 1.16"
 end

spec/rbnacl/libsodium_spec.rb

+# frozen_string_literal: true
+
+RSpec.describe RbNaCl::Libsodium do
+  it "has a version number" do
+    expect(RbNaCl::Libsodium::VERSION).to be_a(String)
+  end
+end

spec/spec_helper.rb

+# frozen_string_literal: true
+
+require "bundler/setup"
+require "rbnacl/libsodium"
+
+RSpec.configure do |config|
+  # Enable flags like --only-failures and --next-failure
+  config.example_status_persistence_file_path = ".rspec_status"
+
+  # Disable RSpec exposing methods globally on `Module` and `main`
+  config.disable_monkey_patching!
+
+  config.expect_with :rspec do |c|
+    c.syntax = :expect
+  end
+end