Add image optimization pre-commit plugin

Change-Id: I0817b9ff0b392d6e30b4c268d1a7a71e836123b8
Reviewed-on: https://gerrit.causes.com/30488
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>

Author: gsmendoza

lib/overcommit/plugins/pre_commit/image_optimization.rb

@@ -0,0 +1,48 @@
+require 'image_optim'
+
+module Overcommit::GitHook
+  class ImageOptimization < HookSpecificCheck
+    include HookRegistry
+    file_types :gif, :jpg, :png
+
+    def run_check
+      optimized_images =
+        begin
+          ImageSet.new(staged.map(&:original_path)).optimize!
+        rescue ImageOptim::BinNotFoundError => e
+          return :stop,
+            "#{e.message}. The image_optim gem is dependendent on this binary. " <<
+            "See https://github.com/toy/image_optim for more info."
+        end
+
+      if optimized_images.any?
+        return :bad,
+          "Optimized #{optimized_images.map(&:to_s).inspect}. " <<
+            " Please add them to your commit."
+      else
+        return :good
+      end
+    end
+
+    class ImageSet
+      attr_reader :image_paths
+
+      def initialize(image_paths)
+        @image_paths ||= image_paths
+      end
+
+      def image_optim
+        @image_optim ||= ImageOptim.new(pngout: false)
+      end
+
+      def optimize!
+        results =
+          image_optim.optimize_images!(image_paths) do |path, was_optimized|
+            path if was_optimized
+          end
+
+        results.compact
+      end
+    end
+  end
+end

overcommit.gemspec

@@ -21,5 +21,7 @@ Gem::Specification.new do |s|
             Dir['bin/**/*'] +
             Dir['config/*.yml']
 
+  s.add_runtime_dependency "image_optim"
+
   s.add_development_dependency 'rspec', '2.13.0'
 end

spec/plugins/pre_commit/image_optimization/image_set_spec.rb

@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe Overcommit::GitHook::ImageOptimization::ImageSet do
+  describe "#initialize(image_paths)" do
+    let(:path) { '/tmp/filename.jpg20131024-7103-s1d6n9.jpg' }
+
+    it "sets the image_paths of the image set" do
+      image_set = described_class.new([path])
+      expect(image_set.image_paths).to eq([path])
+    end
+  end
+
+  describe "#optimize!" do
+    let(:optimized_image) { '/tmp/optimized.jpg' }
+    let(:unoptimized_image) { '/tmp/unoptimized.jpg' }
+    let(:image_optim) { stub(ImageOptim) }
+
+    it "excludes already optimized images from the results" do
+      ImageOptim.should_receive(:new).and_return(image_optim)
+
+      image_optim.should_receive(:optimize_images!)
+        .with([unoptimized_image, optimized_image])
+        .and_yield(unoptimized_image, true)
+        .and_yield(optimized_image, false)
+        .and_return([unoptimized_image])
+
+      image_set = described_class.new([unoptimized_image, optimized_image])
+      results = image_set.optimize!
+      expect(results).to eq([unoptimized_image])
+    end
+  end
+
+  describe "image_optim" do
+    it "should be an ImageOptim" do
+      image_set = described_class.new([])
+      expect(image_set.image_optim).to be_a(ImageOptim)
+    end
+  end
+end

spec/plugins/pre_commit/image_optimization_spec.rb

@@ -0,0 +1,66 @@
+require 'spec_helper'
+
+describe Overcommit::GitHook::ImageOptimization do
+  describe '.filetypes' do
+    it "includes only image filetypes" do
+      expect(described_class.filetypes).to eq([:gif, :jpg, :png])
+    end
+  end
+
+  describe "#run_check" do
+    let(:staged_filename) { 'filename.jpg' }
+
+    around do |example|
+      repo do
+        FileUtils.touch staged_filename
+        `git add #{staged_filename}`
+        example.run
+      end
+    end
+
+    context "when a dependency of image_optim is not installed" do
+      let(:image_set) { stub(described_class::ImageSet) }
+
+      before do
+        described_class::ImageSet
+          .should_receive(:new)
+          .with([staged_filename])
+          .and_return(image_set)
+
+        image_set.should_receive(:optimize!).and_raise(ImageOptim::BinNotFoundError)
+      end
+
+      it { should stop }
+    end
+
+    context "when some staged files were optimized" do
+      let(:image_set) { stub(described_class::ImageSet) }
+
+      before do
+        described_class::ImageSet
+          .should_receive(:new)
+          .with([staged_filename])
+          .and_return(image_set)
+
+        image_set.should_receive(:optimize!).and_return([staged_filename])
+      end
+
+      it { should fail_check }
+    end
+
+    context "when no staged files were optimized" do
+      let(:image_set) { stub(described_class::ImageSet) }
+
+      before do
+        described_class::ImageSet
+          .should_receive(:new)
+          .with([staged_filename])
+          .and_return(image_set)
+
+        image_set.should_receive(:optimize!).and_return([])
+      end
+
+      it { should pass }
+    end
+  end
+end