Added ambiguous error

lib/capybara.rb

@@ -7,6 +7,7 @@ module Capybara
   class DriverNotFoundError < CapybaraError; end
   class FrozenInTime < CapybaraError; end
   class ElementNotFound < CapybaraError; end
+  class Ambiguous < ElementNotFound; end
   class ExpectationNotMet < ElementNotFound; end
   class FileNotFound < CapybaraError; end
   class UnselectNotAllowed < CapybaraError; end

lib/capybara/result.rb

@@ -21,14 +21,20 @@ module Capybara
     end
 
     def find!
-      raise Capybara::ElementNotFound, failure_message(true) if @filtered_elements.count != 1
+      raise find_error if @filtered_elements.count != 1
       @filtered_elements.first
     end
 
-    def failure_message(find=false)
-      if find
-        "Unable to find #{@query.description}"
-      elsif @query.options[:count]
+    def find_error
+      if @filtered_elements.count == 0
+        Capybara::ElementNotFound.new("Unable to find #{@query.description}")
+      elsif @filtered_elements.count > 1
+        Capybara::Ambiguous.new("Ambiguous match, found #{@filtered_elements.count} elements matching #{@query.description}")
+      end
+    end
+
+    def failure_message
+      if @query.options[:count]
         "expected #{@query.description} to be returned #{@query.options[:count]} times"
       else
         "expected #{@query.description} to return something"

lib/capybara/spec/session/find_spec.rb

@@ -19,7 +19,7 @@ shared_examples_for "find" do
     end
 
     it "should raise an error if there are multiple matches" do
-      expect { @session.find('//a') }.to raise_error(Capybara::ElementNotFound)
+      expect { @session.find('//a') }.to raise_error(Capybara::Ambiguous)
     end
 
     describe 'the returned node' do