[#2330] Uptime should not make redundant system calls

Rewrite of uptime facts and supporting utility methods. Works on unix,
BSD, windows. No longer makes redundant system calls.

Uses Facter::Util::Uptime utility methods:

* Implemented uptime_seconds_unix using /proc/uptime or who -b on unix,
  sysctl on BSD.

  Added unit tests for the behaviors of get_uptime_seconds_unix: read
  from proc/uptime, read uptime from "sysctl -b kern.boottime", read
  uptime from "who -b", and return nil if nothing else works.

* Implemented uptime_seconds_win using the Win32 API.

Facts implemented:

* uptime_{seconds,hours,days}

    Returns the respective integer value.

* uptime

    Returns human readable uptime statistic that preserves original
    behavior.

    Examples:

      3 days
      1 day
      5:08 hours
      0:35 hours

6 files changed, 169 insertions, 0 deletions

diff --git a/spec/fixtures/uptime/sysctl_kern_boottime b/spec/fixtures/uptime/sysctl_kern_boottime
new file mode 100644
index 0000000..0c54fe4
--- /dev/null
+++ b/spec/fixtures/uptime/sysctl_kern_boottime
diff --git a/spec/fixtures/uptime/ubuntu_proc_uptime b/spec/fixtures/uptime/ubuntu_proc_uptime
new file mode 100644
index 0000000..7e8ed74
--- /dev/null
+++ b/spec/fixtures/uptime/ubuntu_proc_uptime
@@ -0,0 +1 @@
+5097686.63 40756306.43
diff --git a/spec/fixtures/uptime/who_b_boottime b/spec/fixtures/uptime/who_b_boottime
new file mode 100644
index 0000000..9b29dcd
--- /dev/null
+++ b/spec/fixtures/uptime/who_b_boottime
@@ -0,0 +1 @@
+reboot   ~        Aug  1 14:13 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 34992d7..c8bd547 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,5 +1,7 @@
 dir = File.expand_path(File.dirname(__FILE__))
 
+SPECDIR = dir
+
 $LOAD_PATH.unshift("#{dir}/")
 $LOAD_PATH.unshift("#{dir}/../lib")
 
diff --git a/spec/unit/uptime.rb b/spec/unit/uptime.rb
new file mode 100644
index 0000000..19a55fe
--- /dev/null
+++ b/spec/unit/uptime.rb
@@ -0,0 +1,112 @@
+#!/usr/bin/env ruby
+
+require File.dirname(__FILE__) + '/../spec_helper'
+
+require 'facter'
+require 'facter/util/uptime'
+
+describe "uptime facts:" do
+  before { Facter.clear }
+  after { Facter.clear }
+
+  context "when uptime information is available" do
+    describe "uptime" do
+      test_cases = [
+        [60 * 60 * 24 * 3,      '3 days'],
+        [60 * 60 * 24 * 3 + 25, '3 days'],
+        [60 * 60 * 24 * 1,      '1 day'],
+        [60 * 60 * 24 * 1 + 25, '1 day'],
+        [60 * (60 * 3 + 45),    '3:45 hours'],
+        [60 * (60 * 3 + 4),     '3:04 hours'],
+        [60 * 60,               '1:00 hours'],
+        [60 * 35,               '0:35 hours']
+      ]
+
+      test_cases.each do |seconds, expected|
+        it "should return #{expected.inspect} for #{seconds} seconds" do
+          Facter::Util::Uptime.stubs(:get_uptime_seconds_unix).returns(seconds)
+          Facter::Util::Uptime.stubs(:get_uptime_seconds_win).returns(seconds)
+
+          Facter.fact(:uptime).value.should == expected
+        end
+      end
+    end
+
+  end
+
+  context "when uptime information is available" do
+    before do
+      Facter::Util::Uptime.stubs(:get_uptime_seconds_unix).returns(60 * 60 * 24 + 23)
+      Facter::Util::Uptime.stubs(:get_uptime_seconds_win).returns(60 * 60 * 24 + 23)
+    end
+
+    describe "uptime_seconds" do
+      it "should return the uptime in seconds" do
+        Facter.fact(:uptime_seconds).value.should == 60 * 60 * 24 + 23
+      end
+    end
+
+    describe "uptime_hours" do
+      it "should return the uptime in hours" do
+        Facter.fact(:uptime_hours).value.should == 24
+      end
+    end
+
+    describe "uptime_days" do
+      it "should return the uptime in days" do
+        Facter.fact(:uptime_days).value.should == 1
+      end
+    end
+  end
+
+  context "when uptime information is not available" do
+    before do
+      Facter::Util::Uptime.stubs(:get_uptime_seconds_unix).returns(nil)
+      Facter::Util::Uptime.stubs(:get_uptime_seconds_win).returns(nil)
+      $stderr, @old = StringIO.new, $stderr
+    end
+
+    after do
+      $stderr = @old
+    end
+
+    describe "uptime" do
+      it "should return 'unknown'" do
+        Facter.fact(:uptime).value.should == "unknown"
+      end
+    end
+
+    describe "uptime_seconds" do
+      it "should return nil" do
+        Facter.fact(:uptime_seconds).value.should == nil
+      end
+
+      it "should not print a warn message to stderr" do
+        Facter.fact(:uptime_seconds).value
+        $stderr.string.should == ""
+      end
+    end
+
+    describe "uptime_hours" do
+      it "should return nil" do
+        Facter.fact(:uptime_hours).value.should == nil
+      end
+
+      it "should not print a warn message to stderr" do
+        Facter.fact(:uptime_hours).value
+        $stderr.string.should == ""
+      end
+    end
+
+    describe "uptime_days" do
+      it "should return nil" do
+        Facter.fact(:uptime_days).value.should == nil
+      end
+
+      it "should not print a warn message to stderr" do
+        Facter.fact(:uptime_days).value
+        $stderr.string.should == ""
+      end
+    end
+  end
+end
diff --git a/spec/unit/util/uptime.rb b/spec/unit/util/uptime.rb
new file mode 100644
index 0000000..9ba6665
--- /dev/null
+++ b/spec/unit/util/uptime.rb
@@ -0,0 +1,53 @@
+#!/usr/bin/env ruby
+
+require File.dirname(__FILE__) + '/../../spec_helper'
+
+require 'facter/util/uptime'
+
+describe Facter::Util::Uptime do
+
+  describe ".get_uptime_seconds_unix" do
+    context "when /proc/uptime is available" do
+      before do
+        uptime_file = File.join(SPECDIR, "fixtures", "uptime", "ubuntu_proc_uptime")
+        Facter::Util::Uptime.stubs(:uptime_file).returns(uptime_file)
+      end
+
+      it "should return the uptime in seconds as an integer" do
+        Facter::Util::Uptime.get_uptime_seconds_unix.should == 5097686
+      end
+
+    end
+
+    it "should use sysctl kern.boottime when /proc/uptime not available" do
+      nonexistent_file = '/non/existent/file'
+      File.exists?(nonexistent_file).should == false
+      Facter::Util::Uptime.stubs(:uptime_file).returns(nonexistent_file)
+      sysctl_output_file = File.join(SPECDIR, 'fixtures', 'uptime', 'sysctl_kern_boottime') # Aug 01 14:13:47 -0700 2010
+      Facter::Util::Uptime.stubs(:uptime_sysctl_cmd).returns("cat #{sysctl_output_file}")
+      Time.stubs(:now).returns Time.parse("Aug 01 15:13:47 -0700 2010") # one hour later
+      Facter::Util::Uptime.get_uptime_seconds_unix.should == 60 * 60
+    end
+
+    it "should use who -b when neither /proc/uptime nor sysctl kern.boottime is available" do
+      nonexistent_file = '/non/existent/file'
+      File.exists?(nonexistent_file).should == false
+      Facter::Util::Uptime.stubs(:uptime_file).returns(nonexistent_file)
+      Facter::Util::Uptime.stubs(:uptime_sysctl_cmd).returns("cat #{nonexistent_file}")
+      who_b_output_file = File.join(SPECDIR, 'fixtures', 'uptime', 'who_b_boottime') # Aug 1 14:13
+      Facter::Util::Uptime.stubs(:uptime_who_cmd).returns("cat #{who_b_output_file}")
+      Time.stubs(:now).returns Time.parse("Aug 01 15:13") # one hour later
+      Facter::Util::Uptime.get_uptime_seconds_unix.should == 60 * 60
+    end
+
+    it "should return nil when none of /proc/uptime, sysctl kern.boottime, or who -b is available" do
+      nonexistent_file = '/non/existent/file'
+      File.exists?(nonexistent_file).should == false
+      Facter::Util::Uptime.stubs(:uptime_file).returns(nonexistent_file)
+      Facter::Util::Uptime.stubs(:uptime_sysctl_cmd).returns("cat #{nonexistent_file}")
+      Facter::Util::Uptime.stubs(:uptime_who_cmd).returns("cat #{nonexistent_file}")
+      Facter::Util::Uptime.get_uptime_seconds_unix.should == nil
+    end
+  end
+
+end