Expand VERSION (number) into it's own module to give the version number tracking more modularity

CHANGELOG.md

@@ -4,6 +4,7 @@
   - [#372](https://github.com/airblade/paper_trail/pull/372) - Use [Arel](https://github.com/rails/arel) for SQL construction.
   - [#347](https://github.com/airblade/paper_trail/pull/347) - Autoload `ActiveRecord` models in via a `Rails::Engine` when
     the gem is used with `Rails`.
+  - Expand `PaperTrail::VERSION` into a module, mimicking the form used by Rails to give it some additional modularity & versatility.
   - Fixed `VersionConcern#index` instance method so that it conforms to using the primary key for ordering when possible.
 
 ## 3.0.2

lib/paper_trail/version_number.rb

@@ -1,3 +1,18 @@
 module PaperTrail
-  VERSION = '3.0.2'
+  module VERSION
+    MAJOR = 3
+    MINOR = 0
+    TINY  = 3
+    PRE   = 'alpha'
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
+
+    def self.to_s
+      STRING
+    end
+  end
+
+  def self.version
+    VERSION::STRING
+  end
 end

paper_trail.gemspec

@@ -3,7 +3,7 @@ require 'paper_trail/version_number'
 
 Gem::Specification.new do |s|
   s.name          = 'paper_trail'
-  s.version       = PaperTrail::VERSION
+  s.version       = PaperTrail.version
   s.platform      = Gem::Platform::RUBY
   s.summary       = "Track changes to your models' data. Good for auditing or versioning."
   s.description   = s.summary

spec/modules/version_number_spec.rb

@@ -0,0 +1,44 @@
+require 'spec_helper'
+
+describe 'PaperTrail::VERSION' do
+
+  describe "Constants" do
+    subject { PaperTrail::VERSION }
+
+    describe :MAJOR do
+      it { should be_const_defined(:MAJOR) }
+      it { subject::MAJOR.should be_a(Integer) }
+    end
+    describe :MINOR do
+      it { should be_const_defined(:MINOR) }
+      it { subject::MINOR.should be_a(Integer) }
+    end
+    describe :TINY do
+      it { should be_const_defined(:TINY) }
+      it { subject::TINY.should be_a(Integer) }
+    end
+    describe :PRE do
+      it { should be_const_defined(:PRE) }
+      if PaperTrail::VERSION::PRE
+        it { subject::PRE.should be_instance_of(String) }
+      end
+    end
+    describe :STRING do
+      it { should be_const_defined(:STRING) }
+      it { subject::STRING.should be_instance_of(String) }
+
+      it "should join the numbers into a period separated string" do
+        subject::STRING.should ==
+          [subject::MAJOR, subject::MINOR, subject::TINY, subject::PRE].compact.join('.')
+      end
+    end
+  end
+
+end
+
+describe PaperTrail do
+  describe :version do
+    it { should respond_to(:version) }
+    its(:version) { should == PaperTrail::VERSION::STRING }
+  end
+end