Add GitConfig.comment_character method

Retrieve the character which git will use to indicate comments in commit
message templates.

Author: aschrab

lib/overcommit.rb

@@ -10,6 +10,7 @@
 require 'overcommit/hook/base'
 require 'overcommit/hook_context/base'
 require 'overcommit/hook_context'
+require 'overcommit/git_config'
 require 'overcommit/git_repo'
 require 'overcommit/hook_signer'
 require 'overcommit/hook_loader/base'

lib/overcommit/git_config.rb

@@ -0,0 +1,12 @@
+module Overcommit
+  # Get configuration options from git
+  module GitConfig
+    module_function
+
+    def comment_character
+      char = `git config --get core.commentchar`.chomp
+      char = '#' if char == ''
+      char
+    end
+  end
+end

spec/overcommit/git_config_spec.rb

@@ -0,0 +1,25 @@
+require 'spec_helper'
+
+describe Overcommit::GitConfig do
+  describe '.comment_character' do
+    subject { described_class.comment_character }
+
+    context 'with no configuration' do
+      it 'should be "#"' do
+        repo do
+          `git config --local core.commentchar ''`
+          expect(subject).to eq '#'
+        end
+      end
+    end
+
+    context 'with custom configuration' do
+      it 'should be the configured character' do
+        repo do
+          `git config --local core.commentchar x`
+          expect(subject).to eq 'x'
+        end
+      end
+    end
+  end
+end