From d52e6ea10e1239cfe3f9e568f2a75f07154cab52 Mon Sep 17 00:00:00 2001
From: Sven Weidauer <sven@5sw.de>
Date: Sun, 29 May 2022 12:17:28 +0200
Subject: [PATCH] Prepare for testing

---
 Gemfile.lock          |  3 ++
 format-staged.gemspec |  3 +-
 spec/git.rb           | 72 +++++++++++++++++++++++++++++++++++++++++++
 spec/test_spec.rb     | 22 +++++++++++++
 4 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 spec/git.rb
 create mode 100644 spec/test_spec.rb

diff --git a/Gemfile.lock b/Gemfile.lock
index 1576cac..f7fd5a9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -45,6 +45,8 @@ GEM
       parser (>= 3.1.1.0)
     rubocop-rake (0.6.0)
       rubocop (~> 1.0)
+    rubocop-rspec (2.11.1)
+      rubocop (~> 1.19)
     ruby-progressbar (1.11.0)
     unicode-display_width (2.1.0)
 
@@ -58,6 +60,7 @@ DEPENDENCIES
   rspec
   rubocop (~> 1.29)
   rubocop-rake (~> 0.6)
+  rubocop-rspec
 
 BUNDLED WITH
    2.1.4
diff --git a/format-staged.gemspec b/format-staged.gemspec
index e48cb9e..8640d53 100644
--- a/format-staged.gemspec
+++ b/format-staged.gemspec
@@ -20,9 +20,10 @@ Gem::Specification.new do |s|
   s.add_dependency 'colorize'
 
   s.add_development_dependency 'rake', '~> 13.0'
+  s.add_development_dependency 'rspec'
   s.add_development_dependency 'rubocop', '~> 1.29'
   s.add_development_dependency 'rubocop-rake', '~> 0.6'
-  s.add_development_dependency 'rspec'
+  s.add_development_dependency 'rubocop-rspec'
 
   s.metadata = {
     'rubygems_mfa_required' => 'true'
diff --git a/spec/git.rb b/spec/git.rb
new file mode 100644
index 0000000..6d5ec56
--- /dev/null
+++ b/spec/git.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require 'tmpdir'
+require 'fileutils'
+require 'English'
+
+##
+# Test helpers for managing a git repository
+module Git
+  ##
+  # A git repository
+  class Repo
+    attr_reader :path
+
+    def initialize
+      @path = Dir.mktmpdir
+
+      git 'init'
+    end
+
+    def file_in_tree(name, content)
+      set_content name, content
+      stage name
+      commit "Add #{name}"
+    end
+
+    def set_content(name, content)
+      absolute = Pathname.new(path) + name
+
+      FileUtils.mkdir_p absolute.dirname
+      File.write absolute, content.end_with?("\n") ? content : "#{content}\n"
+    end
+
+    def stage(file)
+      git 'add', file
+    end
+
+    def commit(message)
+      git 'commit', '-m', message
+    end
+
+    def content(file)
+      git 'show', ":#{file}"
+    end
+
+    def cleanup
+      FileUtils.remove_entry path
+    end
+
+    def git(*cmd)
+      in_repo do
+        output = IO.popen(['git'] + cmd) do |io|
+          io.read.chomp
+        end
+
+        raise 'Failed to run git' unless $CHILD_STATUS.success?
+
+        output
+      end
+    end
+
+    def in_repo(&block)
+      Dir.chdir path, &block
+    end
+  end
+
+  def self.new_repo
+    repo = Repo.new
+    yield repo if block_given?
+    repo
+  end
+end
diff --git a/spec/test_spec.rb b/spec/test_spec.rb
new file mode 100644
index 0000000..778f761
--- /dev/null
+++ b/spec/test_spec.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require_relative 'git'
+
+require 'format_staged'
+
+describe FormatStaged do
+  def repo
+    @repo ||= Git.new_repo do |r|
+      r.file_in_tree 'index.js', <<~CONTENT
+        function foo () {
+          return 'foo'
+        }
+      CONTENT
+    end
+  end
+
+  after :each do
+    @repo&.cleanup
+    @repo = nil
+  end
+end