Tightened up git checking to check for a minimum installed version of

Git.

lib/homesick.rb

@@ -8,6 +8,7 @@ require 'homesick/cli'
 # Homesick's top-level module
 module Homesick
   GITHUB_NAME_REPO_PATTERN = /\A([A-Za-z0-9_-]+\/[A-Za-z0-9_-]+)\Z/
+  GIT_VERSION_PATTERN = /[#{Homesick::Actions::GitActions::MAJOR}-9]\.[#{Homesick::Actions::GitActions::MINOR}-9]\.[#{Homesick::Actions::GitActions::PATCH}-9]/
   SUBDIR_FILENAME = '.homesick_subdir'
 
   DEFAULT_CASTLE_NAME = 'dotfiles'

lib/homesick/actions/git_actions.rb

@@ -3,6 +3,12 @@ module Homesick
   module Actions
     # Git-related helper methods for Homesick
     module GitActions
+      # Information on the minimum git version required for Homesick
+      MAJOR = 2
+      MINOR = 0
+      PATCH = 0
+      STRING = [MAJOR, MINOR, PATCH].compact.join('.')
+
       # TODO: move this to be more like thor's template, empty_directory, etc
       def git_clone(repo, config = {})
         config ||= {}

lib/homesick/cli.rb

@@ -20,8 +20,8 @@ module Homesick
     def initialize(args = [], options = {}, config = {})
       super
       # Check if git is installed
-      unless `git --version`.size > 0
-        say_status :error, 'Git must be installed to use Homesick', :red
+      unless `git --version` =~ GIT_VERSION_PATTERN
+        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

spec/homesick_cli_spec.rb

@@ -24,6 +24,19 @@ describe Homesick::CLI do
       end
     end
 
+    context 'when git is installed' do
+      before do
+        # The following line suppresses Thor warnings about overriding methods.
+        allow($stdout).to receive(:write).at_least(:once)
+        expect_any_instance_of(Homesick::CLI).to receive(:`).and_return(Homesick::Actions::GitActions::STRING)
+      end
+      it 'should not raise an exception when Git is installed' do
+        output = Capture.stdout{ expect{Homesick::CLI.new}.not_to raise_error }
+        expect(output.chomp).not_to match(/#{Regexp.escape(Homesick::Actions::GitActions::STRING)}/)
+      end
+
+    end
+
     context 'when git is not installed' do
       before do
         # The following line suppresses Thor warnings about overriding methods.
@@ -31,7 +44,8 @@ describe Homesick::CLI do
         expect_any_instance_of(Homesick::CLI).to receive(:`).and_return('')
       end
       it 'should raise an exception when Git is not installed' do
-        Capture.stdout{ expect{Homesick::CLI.new}.to raise_error SystemExit }
+        output = Capture.stdout{ expect{Homesick::CLI.new}.to raise_error SystemExit }
+        expect(output.chomp).to match(/#{Regexp.escape(Homesick::Actions::GitActions::STRING)}/)
       end
     end
   end
@@ -695,7 +709,7 @@ 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