Provides timeout similar to standard library Timeout, but avoids threads

Capybara::WaitUntil
- should return result of yield if it returns true value within timeout
- should keep trying within timeout
- should raise Capybara::TimeoutError if block fails to return true within timeout

lib/capybara/wait_until.rb

@@ -0,0 +1,23 @@
+module Capybara
+  #Provides timeout similar to standard library Timeout, but avoids threads
+  class WaitUntil
+    
+    class << self
+      
+      def timeout(seconds = 1, &block)
+        start_time = Time.now
+        
+        result = nil
+        
+        until result 
+          return result if result = yield
+          
+          if (Time.now - start_time) > seconds
+             raise TimeoutError
+          end
+        end                 
+      end
+      
+    end   
+  end
+end

spec/wait_until_spec.rb

@@ -0,0 +1,28 @@
+require File.expand_path('spec_helper', File.dirname(__FILE__))
+
+require 'capybara'
+require 'capybara/wait_until'
+
+module Capybara
+  
+  describe WaitUntil do
+    
+    it "should return result of yield if it returns true value within timeout" do
+      WaitUntil.timeout { "hello" }.should == "hello"
+    end
+    
+    it "should keep trying within timeout" do
+      count = 0
+      WaitUntil.timeout { count += 1; count == 5 ? count : nil }.should == 5
+    end
+    
+    it "should raise Capybara::TimeoutError if block fails to return true within timeout" do
+      running do 
+        WaitUntil.timeout(0.1) { false }
+      end.should raise_error(::Capybara::TimeoutError)
+    end
+    
+  end
+  
+end
+