Merge pull request #127 from JCook21/CheckGit

In lieu of other comments I'm going to go ahead and merge this.

lib/homesick/actions/git_actions.rb

@@ -3,6 +3,25 @@ module Homesick
   module Actions
     # Git-related helper methods for Homesick
     module GitActions
+      # Information on the minimum git version required for Homesick
+      MIN_VERSION = {
+        major: 1,
+        minor: 8,
+        patch: 0
+      }
+      STRING = MIN_VERSION.values.join('.')
+
+      def git_version_correct?
+        info = `git --version`.scan(/(\d+)\.(\d+)\.(\d+)/).flatten.map(&:to_i)
+        return false unless info.count == 3
+        current_version = Hash[ [:major, :minor, :patch].zip(info) ]
+        return true if current_version.eql?(MIN_VERSION)
+        current_version.each do |k,v|
+          return true if v > MIN_VERSION[k]
+        end
+        false
+      end
+
       # TODO: move this to be more like thor's template, empty_directory, etc
       def git_clone(repo, config = {})
         config ||= {}

lib/homesick/cli.rb

@@ -19,8 +19,13 @@ module Homesick
 
     def initialize(args = [], options = {}, config = {})
       super
-      self.shell = Thor::Shell::Color.new
+      # Check if git is installed
+      unless git_version_correct?
+        say_status :error, "Git version >= #{Homesick::Actions::GitActions::STRING} must be installed to use Homesick", :red
+        exit(1)
+      end
       # Hack in support for diffing symlinks
+      self.shell = Thor::Shell::Color.new
       class << shell
         def show_diff(destination, content)
           destination = Pathname.new(destination)

spec/homesick_cli_spec.rb

@@ -13,7 +13,7 @@ describe Homesick::CLI do
 
   before { allow(homesick).to receive(:repos_dir).and_return(castles) }
 
-  describe 'smoke test' do
+  describe 'smoke tests' do
     context 'when running bin/homesick' do
       before do
         bin_path = Pathname.new(__FILE__).parent.parent
@@ -23,6 +23,26 @@ describe Homesick::CLI do
         expect(@output.length).to be > 0
       end
     end
+
+    context 'when git is not installed' do
+      before do
+        expect_any_instance_of(Homesick::Actions::GitActions).to receive(:`).and_return("git version 1.0.0")
+      end
+      it 'should raise an exception when' do
+        output = Capture.stdout{ expect{Homesick::CLI.new}.to raise_error SystemExit }
+        expect(output.chomp).to include(Homesick::Actions::GitActions::STRING)
+      end
+    end
+
+    context 'when git is installed' do
+      before do
+        expect_any_instance_of(Homesick::Actions::GitActions).to receive(:`).at_least(:once).and_return("git version #{Homesick::Actions::GitActions::STRING}")
+      end
+      it 'should not raise an exception' do
+        output = Capture.stdout{ expect{Homesick::CLI.new}.not_to raise_error }
+        expect(output.chomp).not_to include(Homesick::Actions::GitActions::STRING)
+      end
+    end
   end
 
   describe 'clone' do
@@ -684,7 +704,7 @@ describe Homesick::CLI do
   describe 'version' do
     it 'prints the current version of homesick' do
       text = Capture.stdout { homesick.version }
-      expect(text.chomp).to match(/\d+\.\d+\.\d+/)
+      expect(text.chomp).to match(/#{Regexp.escape(Homesick::Version::STRING)}/)
     end
   end