Add python release as available facts

lib/facter/python_release.rb

@@ -0,0 +1,33 @@
+# Make python release available as facts
+
+def get_python_release(executable)
+  if Facter::Util::Resolution.which(executable)
+    results = Facter::Util::Resolution.exec("#{executable} -V 2>&1").match(/^.*(\d+\.\d+)\.\d+\+?$/)
+    if results
+      results[1]
+    end
+  end
+end
+
+Facter.add("python_release") do
+  setcode do
+    get_python_release 'python'
+  end
+end
+
+Facter.add("python2_release") do
+  setcode do
+    default_release = get_python_release 'python'
+    if default_release.nil? or !default_release.start_with?('2')
+      get_python_release 'python2'
+    else
+      default_release
+    end
+  end
+end
+
+Facter.add("python3_release") do
+  setcode do
+    get_python_release 'python3'
+  end
+end

spec/unit/facter/python_release_spec.rb

@@ -0,0 +1,98 @@
+require "spec_helper"
+
+describe Facter::Util::Fact do
+  before {
+    Facter.clear
+  }
+
+  let(:python2_version_output) { <<-EOS
+Python 2.7.9
+EOS
+  }
+  let(:python3_version_output) { <<-EOS
+Python 3.3.0
+EOS
+  }
+
+  describe "python_release" do
+    context 'returns Python release when `python` present' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python -V 2>&1").returns(python2_version_output)
+        expect(Facter.value(:python_release)).to eq("2.7")
+      end
+    end
+
+    context 'returns nil when `python` not present' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(false)
+        expect(Facter.value(:python_release)).to eq(nil)
+      end
+    end
+
+  end
+
+  describe "python2_release" do
+    context 'returns Python 2 release when `python` is present and Python 2' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python -V 2>&1").returns(python2_version_output)
+        expect(Facter.value(:python2_release)).to eq('2.7')
+      end
+    end
+
+    context 'returns Python 2 release when `python` is Python 3 and `python2` is present' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python -V 2>&1").returns(python3_version_output)
+        Facter::Util::Resolution.expects(:which).with("python2").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python2 -V 2>&1").returns(python2_version_output)
+        expect(Facter.value(:python2_release)).to eq('2.7')
+      end
+    end
+
+    context 'returns nil when `python` is Python 3 and `python2` is absent' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python -V 2>&1").returns(python3_version_output)
+        Facter::Util::Resolution.expects(:which).with("python2").returns(false)
+        expect(Facter.value(:python2_release)).to eq(nil)
+      end
+    end
+
+    context 'returns nil when `python2` and `python` are absent' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python").returns(false)
+        Facter::Util::Resolution.expects(:which).with("python2").returns(false)
+        expect(Facter.value(:python2_release)).to eq(nil)
+      end
+    end
+
+  end
+
+  describe "python3_release" do
+    context 'returns Python 3 release when `python3` present' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python3").returns(true)
+        Facter::Util::Resolution.expects(:exec).with("python3 -V 2>&1").returns(python3_version_output)
+        expect(Facter.value(:python3_release)).to eq("3.3")
+      end
+    end
+
+    context 'returns nil when `python3` not present' do
+      it do
+        Facter::Util::Resolution.stubs(:exec)
+        Facter::Util::Resolution.expects(:which).with("python3").returns(false)
+        expect(Facter.value(:python3_release)).to eq(nil)
+      end
+    end
+
+  end
+end