Support duck typed commits and switch to Rspec

.rspec

@@ -0,0 +1,2 @@
+--require spec_helper
+--color

README.md

@@ -25,10 +25,16 @@ Or install it yourself as:
 Create a Transaction which contains all of your commits. Note that the Transaction will run as soon as it is
 initialized.
 
-    UpAndAtThem::Transaction.new([
-        UpAndAtThem::Commit.new { puts "do something!" }.on_rollback { "undo something!" },
-        UpAndAtThem::Commit.new { puts "do something else!" }.on_rollback { "undo something else!" },
-    ])
+    UpAndAtThem::Transaction[
+      UpAndAtThem::Commit.new { puts "do something!" }.on_rollback { "undo something!" },
+      UpAndAtThem::Commit.new { puts "do something else!" }.on_rollback { "undo something else!" }
+    ]
+
+The `UpAndAtThem::Transaction` array can contain any classes that respond to `#call` and `#rollback`. The
+`UpAndAtThem::Commit` class allows you to define those methods easily:
+
+    UpAndAtThem::Commit.new { "this block will execute on #call" }.on_rollback { "this block will execute on #rollback" }
+    UpAndAtThem::Commit.new { "calling on_rollback is not necessary" }
 
 See the tests for other example Commit actions within a Transaction.
 

lib/up_and_at_them.rb

@@ -1,47 +1,3 @@
-require "up_and_at_them/version"
-
-module UpAndAtThem
-  class Commit
-    def initialize(&block)
-      raise LocalJumpError unless block_given?
-      @block = block
-    end
-    def on_rollback(&block)
-      raise LocalJumpError unless block_given?
-      @rollback = block
-      self
-    end
-    def call
-      @block.call
-    end
-    def rollback
-      @rollback.call if @rollback
-    end
-  end
-
-  class Transaction
-    def initialize(tasks)
-      tasks = Array(tasks)
-      tasks.each do |t|
-        Commit === t or raise TypeError
-      end
-      @tasks = tasks
-      run
-    end
-
-    def run
-      finished_tasks = []
-      begin
-        @tasks.each do |task|
-          task.call
-          finished_tasks << task
-        end
-      rescue => err
-        finished_tasks.reverse_each do |task|
-          task.rollback
-        end
-        raise err
-      end
-    end
-  end
-end
+require 'up_and_at_them/version'
+require 'up_and_at_them/commit'
+require 'up_and_at_them/transaction'

lib/up_and_at_them/commit.rb

@@ -0,0 +1,24 @@
+module UpAndAtThem
+  class Commit
+
+    def initialize(&block)
+      raise LocalJumpError unless block_given?
+      @block = block
+    end
+
+    def on_rollback(&block)
+      raise LocalJumpError unless block_given?
+      @rollback = block
+      self
+    end
+
+    def call
+      @block.call
+    end
+
+    def rollback
+      @rollback.call if @rollback
+    end
+
+  end
+end

lib/up_and_at_them/transaction.rb

@@ -0,0 +1,25 @@
+module UpAndAtThem
+  class Transaction
+
+    def self.[](*tasks)
+      new(tasks)
+    end
+
+    def initialize(tasks)
+      @tasks = Array(tasks)
+      run
+    end
+
+    def run
+      finished_tasks = []
+      @tasks.each do |task|
+        task.call
+        finished_tasks << task
+      end
+    rescue => err
+      finished_tasks.reverse_each(&:rollback)
+      raise err
+    end
+
+  end
+end

spec/spec_helper.rb

@@ -0,0 +1,9 @@
+ENV["RAILS_ENV"] ||= 'test'
+
+require 'rubygems'
+require 'bundler/setup'
+require 'up_and_at_them'
+
+RSpec.configure do |config|
+  config.order = :random
+end

spec/transaction_spec.rb

@@ -0,0 +1,80 @@
+describe UpAndAtThem::Transaction do
+
+  it 'rolls back past commits' do
+    flags = { 1 => :pending, 2 => :pending, 3 => :pending, 4 => :pending }
+    commits = (1...4).map do |i|
+      UpAndAtThem::Commit.new { flags[i] = :committed; if i==3 ; raise 'uh oh!'; end }.on_rollback { flags[i] = :rolled_back }
+    end
+    expect { UpAndAtThem::Transaction.new commits }.to raise_error(RuntimeError)
+    expect(flags[1]).to eq :rolled_back
+    expect(flags[4]).to eq :pending
+    expect(flags[3]).to eq :committed
+    expect(flags[2]).to eq :rolled_back
+  end
+
+  it 'rolls back in reverse commit order' do
+    flags = { 1 => -1, 2 => -1, 3 => -1, 4 => -1 }
+    commits = (1...4).map do |i|
+      UpAndAtThem::Commit.new { flags[i] = -1; if i==3 ; raise 'uh oh!'; end }.on_rollback { flags[i] = Time.now; sleep 1 }
+    end
+    expect { UpAndAtThem::Transaction.new commits }.to raise_error(RuntimeError)
+    expect(flags[4].to_f).to eq -1
+    expect(flags[3].to_f).to be < flags[2].to_f
+    expect(flags[2].to_f).to be < flags[1].to_f
+  end
+
+  it 'allows no-rollback commits' do
+    flags = {1 => :pending, 2 => :pending, 3 => :pending, 4 => :pending}
+    commits = (1...4).map do |i|
+      UpAndAtThem::Commit.new { flags[i] = :committed; if i==3 ; raise 'fail!'; end }
+    end
+    expect { UpAndAtThem::Transaction.new commits }.to raise_error(RuntimeError)
+    expect(flags[4]).to eq :pending
+    expect(flags[3]).to eq :committed
+    expect(flags[2]).to eq :committed
+    expect(flags[1]).to eq :committed
+  end
+
+  describe '.[]' do
+    it 'instantiates a new Transaction' do
+      commit = -> { raise 'fail!' }
+      expect { UpAndAtThem::Transaction[commit] }.to raise_error(RuntimeError)
+    end
+  end
+
+  describe 'duck typed Commits' do
+    class TestCommit
+      attr_reader :state
+
+      def initialize(fail = false)
+        @fail = fail
+        @state = :pending
+      end
+
+      def call
+        @state = :committed
+        raise if @fail
+      end
+
+      def rollback
+        @state = :rolled_back
+      end
+    end
+
+    it 'runs #call on each commit' do
+      commit = TestCommit.new
+      UpAndAtThem::Transaction[commit]
+      expect(commit.state).to eq :committed
+    end
+
+    it 'runs #rollback when the commit fails' do
+      commit1 = TestCommit.new
+      commit2 = TestCommit.new(true)
+      expect { UpAndAtThem::Transaction[commit1, commit2] }.to raise_error
+      expect(commit1.state).to eq :rolled_back
+      expect(commit2.state).to eq :committed
+    end
+
+  end
+
+end

up_and_at_them.gemspec

@@ -20,4 +20,6 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency "bundler", "~> 1.6"
   spec.add_development_dependency "rake"
+  spec.add_development_dependency "rspec"
+
 end