xpath number: fix a bug that false is converted to NaN

GitHub: fix #18

It must be 0.

Reported by Mirko Budszuhn. Thanks!!!

Author: kou

lib/rexml/functions.rb

@@ -66,7 +66,6 @@ def Functions::count( node_set )
     def Functions::id( object )
     end
 
-    # UNTESTED
     def Functions::local_name(node_set=nil)
       get_namespace(node_set) do |node|
         return node.local_name
@@ -386,25 +385,23 @@ def Functions::compare_language lang1, lang2
     #
     # an object of a type other than the four basic types is converted to a
     # number in a way that is dependent on that type
-    def Functions::number( object=nil )
-      object = @@context[:node] unless object
+    def Functions::number(object=@@context[:node])
       case object
       when true
         Float(1)
       when false
         Float(0)
       when Array
-        number(string( object ))
+        number(string(object))
       when Numeric
         object.to_f
       else
-        str = string( object )
-        # If XPath ever gets scientific notation...
-        #if str =~ /^\s*-?(\d*\.?\d+|\d+\.)([Ee]\d*)?\s*$/
-        if str =~ /^\s*-?(\d*\.?\d+|\d+\.)\s*$/
-          str.to_f
+        str = string(object)
+        case str.strip
+        when /\A\s*(-?(?:\d+(?:\.\d*)?|\.\d+))\s*\z/
+          $1.to_f
         else
-          (0.0 / 0.0)
+          Float::NAN
         end
       end
     end

test/rexml/functions/test_number.rb

@@ -1,35 +1,38 @@
 # frozen_string_literal: false
-require 'rexml/document'
-require 'test/unit'
-require 'rexml/functions'
+
+require "test/unit"
+require "rexml/document"
+require "rexml/functions"
 
 module REXMLTests
-  class TC_Rexml_Functions_Number < Test::Unit::TestCase
+  class TestFunctionsNumber < Test::Unit::TestCase
+    def setup
+      REXML::Functions.context = nil
+    end
 
-    def test_functions_number_int
-      telem = REXML::Element.new("elem")
-      telem.text="9"
-      assert_equal(9, REXML::Functions::number(telem))
+    def test_true
+      assert_equal(1, REXML::Functions.number(true))
     end
-    def test_functions_number_float
-      telem = REXML::Element.new("elem")
-      telem.text="10.4"
-      assert_equal(10.4, REXML::Functions::number(telem))
+
+    def test_false
+      assert_equal(0, REXML::Functions.number(false))
     end
-    def test_functions_number_negative_int
-      telem = REXML::Element.new("elem")
-      telem.text="-9"
-      assert_equal(-9, REXML::Functions::number(telem))
+
+    def test_numeric
+      assert_equal(29, REXML::Functions.number(29))
     end
-    def test_functions_number_negative_float
-      telem = REXML::Element.new("elem")
-      telem.text="-9.13"
-      assert_equal(-9.13, REXML::Functions::number(telem))
+
+    def test_string_integer
+      assert_equal(100, REXML::Functions.number("100"))
+    end
+
+    def test_string_float
+      assert_equal(-9.13, REXML::Functions.number("-9.13"))
+    end
+
+    def test_node_set
+      root = REXML::Document.new("<root>100</root>").root
+      assert_equal(100, REXML::Functions.number([root]))
     end
-    #def test_functions_number_scientific_notation
-    #  telem = REXML::Element.new("elem")
-    #  telem.text="9.13E12"
-    #  assert_equal(9.13E12, REXML::Functions::number(telem))
-    #end
   end
 end