From 809ed9bfa60d35b2573a0500feabd516a35a3e14 Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Thu, 28 Aug 2014 09:36:21 +0200
Subject: [PATCH] Handle boolean values in the boolean() function.

---
 lib/oga/xpath/evaluator.rb                     | 9 ++++++---
 spec/oga/xpath/evaluator/calls/boolean_spec.rb | 8 ++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/oga/xpath/evaluator.rb b/lib/oga/xpath/evaluator.rb
index 3c251a9..986a7a9 100644
--- a/lib/oga/xpath/evaluator.rb
+++ b/lib/oga/xpath/evaluator.rb
@@ -1075,12 +1075,15 @@ module Oga
       #
       def on_call_boolean(context, expression)
         retval = process(expression, context)
+        bool   = false
 
         if retval.is_a?(Numeric)
-          return !retval.nan? && !retval.zero?
-        else
-          return retval && !retval.empty?
+          bool = !retval.nan? && !retval.zero?
+        elsif retval
+          bool = !retval.respond_to?(:empty?) || !retval.empty?
         end
+
+        return bool
       end
 
       ##
diff --git a/spec/oga/xpath/evaluator/calls/boolean_spec.rb b/spec/oga/xpath/evaluator/calls/boolean_spec.rb
index e0b3328..a3d99b2 100644
--- a/spec/oga/xpath/evaluator/calls/boolean_spec.rb
+++ b/spec/oga/xpath/evaluator/calls/boolean_spec.rb
@@ -19,6 +19,14 @@ describe Oga::XPath::Evaluator do
       @evaluator.evaluate('boolean(10)').should == true
     end
 
+    example 'return true for a boolean true' do
+      @evaluator.evaluate('boolean(true())').should == true
+    end
+
+    example 'return false for a boolean false' do
+      @evaluator.evaluate('boolean(false())').should == false
+    end
+
     example 'return true for a positive float' do
       @evaluator.evaluate('boolean(10.5)').should == true
     end