Refactors facts about Java version

These facts have since been refactored, ported these changes from https://github.com/puppetlabs/puppetlabs-java/

lib/facter/java_major_version.rb

@@ -17,4 +17,4 @@
     java_version = Facter.value(:java_version)
     java_patch_level = java_version.strip.split('_')[0].split('.')[1] unless java_version.nil?
   end
-end
+end

lib/facter/java_version.rb

@@ -12,8 +12,10 @@
 # Notes:
 #   None
 Facter.add(:java_version) do
+  # This will fail on OS X when Java hasn't been installed yet.
+  next unless Kernel.system "/usr/libexec/java_home --failfast &>/dev/null"
   setcode do
-    if Facter::Util::Resolution.which('java') && Facter::Util::Resolution.exec('/usr/libexec/java_home --failfast &>/dev/null')
+    if Facter::Util::Resolution.which('java')
       Facter::Util::Resolution.exec('java -Xmx8m -version 2>&1').lines.first.split(/"/)[1].strip
     end
   end

spec/unit/facter/java_major_version.rb

@@ -0,0 +1,31 @@
+require "spec_helper"
+
+describe Facter::Util::Fact do
+  before {
+    Facter.clear
+  }
+
+  describe "java_major_version" do
+    context "if java is not installed" do
+      context 'returns java major version extracted from java_version fact' do
+        before :each do
+          allow(Facter.fact(:java_version)).to receive(:value).and_return("1.7.0_71")
+        end
+        it do
+          Facter.fact(:java_major_version).value.should == "7"
+        end
+      end
+    end
+
+    context "if java is not installed" do
+      context 'returns nil' do
+        before :each do
+          allow(Facter.fact(:java_version)).to receive(:value).and_return(nil)
+        end
+        it do
+          Facter.fact(:java_major_version).value.should == nil
+        end
+      end
+    end
+  end
+end

spec/unit/facter/java_version_spec.rb

@@ -13,10 +13,12 @@
 Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
 Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)
         EOS
-        allow(Facter::Util::Resolution).to receive(:which).with("java").
-          and_return(true)
-        allow(Facter::Util::Resolution).to receive(:exec).with("java -version 2>&1").
-          and_return(java_version_output)
+        allow(Facter::Util::Resolution).to receive(:which).
+          with("java").and_return(true)
+        expect(Kernel).to receive(:system).
+          with("/usr/libexec/java_home --failfast &>/dev/null").and_return(true)
+        allow(Facter::Util::Resolution).to receive(:exec).
+          with("java -Xmx8m -version 2>&1").and_return(java_version_output)
         Facter.fact(:java_version).value.should == "1.7.0_71"
       end
     end
@@ -25,7 +27,7 @@
       it do
         allow(Facter::Util::Resolution).to receive(:which).with("java").
           and_return(false)
-        Facter.fact(:java_version).should be_nil
+        Facter.fact(:java_version).value.should be_nil
       end
     end
   end