add mdadmversion fact

lib/facter/mdadmversion.rb

@@ -0,0 +1,9 @@
+Facter.add('mdadmversion') do
+  mdadm = Facter.value(:mdadm)
+  setcode do
+    unless mdadm.nil?
+      # `mdadm --version` sends it's output to stderr
+      Facter::Util::Resolution.exec("#{mdadm} --version 2>&1")
+    end 
+  end
+end

spec/unit/facts/mdadmversion_spec.rb

@@ -0,0 +1,21 @@
+require 'spec_helper'
+
+describe 'mdadmversion', :type => :fact do
+  before(:each) { Facter.clear }
+
+  context 'mdadm fact => /sbin/madam' do
+    it 'should get the version string' do
+      Facter.fact(:mdadm).stubs(:value).returns('/sbin/mdadm')
+      Facter::Util::Resolution.stubs(:exec).with('/sbin/mdadm --version 2>&1').returns('mdadm - v3.2.3 - 23rd December 2011')
+
+      Facter.fact(:mdadmversion).value.should == 'mdadm - v3.2.3 - 23rd December 2011'
+    end
+  end
+
+  context 'mdadm fact not set' do
+    it 'should return nil' do
+      Facter.fact(:mdadm).stubs(:value).returns(nil)
+      Facter.fact(:mdadmversion).value.should be_nil
+    end
+  end
+end