Add pre-commit hook for recess

config/default.yml

@@ -368,6 +368,14 @@ PreCommit:
       - 'db/schema.rb'
       - 'db/structure.sql'
 
+  Recess:
+    enabled: false
+    description: 'Analyzing with recess'
+    required_executable: 'recess'
+    install_command: 'npm install -g recess'
+    flags: ['--format=compact', '--stripColors']
+    include: '**/*.css'
+
   Reek:
     enabled: false
     description: 'Analyzing with Reek'

lib/overcommit/hook/pre_commit/recess.rb

@@ -0,0 +1,18 @@
+module Overcommit::Hook::PreCommit
+  # Runs `recess` against any modified CSS files.
+  #
+  # @see https://twitter.github.io/recess/
+  class Recess < Base
+    MESSAGE_REGEX = /^(?<file>(?:\w:)?[^:]+):(?<line>\d+):.+$/
+
+    def run
+      result = execute(command, args: applicable_files)
+
+      raw_messages = result.stdout.split("\n").grep(MESSAGE_REGEX)
+
+      # example message:
+      #   path/to/file.css:1:Error message
+      extract_messages(raw_messages, MESSAGE_REGEX)
+    end
+  end
+end

spec/overcommit/hook/pre_commit/recess_spec.rb

@@ -0,0 +1,43 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PreCommit::Recess do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    subject.stub(:applicable_files).and_return(%w[file1.css file2.css])
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when recess exits successfully' do
+    let(:result) { double('result') }
+
+    before do
+      result.stub(:success?).and_return(true)
+    end
+
+    context 'with no errors' do
+      before do
+        result.stub(:stdout).and_return(normalize_indent(<<-OUT))
+          FILE: file1.css
+          STATUS: Perfect!
+        OUT
+      end
+
+      it { should pass }
+    end
+
+    context 'and it reports an error' do
+      before do
+        result.stub(:stdout).and_return(normalize_indent(<<-OUT))
+          file1.css:1:Element selectors should not be overqualified
+        OUT
+      end
+
+      it { should fail_hook }
+    end
+  end
+end