Add `exact` option

lib/capybara/query.rb

@@ -2,7 +2,7 @@ module Capybara
   class Query
     attr_accessor :selector, :locator, :options, :xpath, :find, :negative
 
-    VALID_KEYS = [:text, :visible, :between, :count, :maximum, :minimum]
+    VALID_KEYS = [:text, :visible, :between, :count, :maximum, :minimum, :exact]
 
     def initialize(*args)
       @options = if args.last.is_a?(Hash) then args.pop.dup else {} end
@@ -20,7 +20,13 @@ module Capybara
       end
       @selector ||= Selector.all[Capybara.default_selector]
 
-      @xpath = @selector.call(@locator).to_s
+      @xpath = @selector.call(@locator)
+      if @xpath.respond_to?(:to_xpath) and @options[:exact]
+        @xpath = @xpath.to_xpath(:exact)
+      else
+        @xpath = @xpath.to_s
+      end
+
 
       assert_valid_keys!
     end

lib/capybara/spec/session/find_spec.rb

@@ -113,6 +113,24 @@ Capybara::SpecHelper.spec '#find' do
     @session.find(@xpath).value.should == 'John'
   end
 
+  context "with :exact option" do
+    it "matches exactly when true" do
+      @session.find(:xpath, XPath.descendant(:input)[XPath.attr(:id).is("test_field")], :exact => true).value.should == "monkey"
+      expect do
+        @session.find(:xpath, XPath.descendant(:input)[XPath.attr(:id).is("est_fiel")], :exact => true)
+      end.to raise_error(Capybara::ElementNotFound)
+    end
+
+    it "matches loosely when false" do
+      @session.find(:xpath, XPath.descendant(:input)[XPath.attr(:id).is("test_field")], :exact => false).value.should == "monkey"
+      @session.find(:xpath, XPath.descendant(:input)[XPath.attr(:id).is("est_fiel")], :exact => false).value.should == "monkey"
+    end
+
+    it "defaults to `Capybara.exact`" do
+
+    end
+  end
+
   context "within a scope" do
     before do
       @session.visit('/with_scope')

xpath

@@ -1 +1 @@
-Subproject commit 130b0192a8fbbff6110efc306b33697be66c631e
+Subproject commit 4c7c3351f970f14635e670239e11f81fffb07717