Raise errors in main thread when error in application occurs, closes #660

lib/capybara/server.rb

@@ -4,7 +4,9 @@ require 'rack'
 
 module Capybara
   class Server
-    class Identify
+    class Middleware
+      attr_accessor :error
+
       def initialize(app)
         @app = app
       end
@@ -13,7 +15,12 @@ module Capybara
         if env["PATH_INFO"] == "/__identify__"
           [200, {}, [@app.object_id.to_s]]
         else
-          @app.call(env)
+          begin
+            @app.call(env)
+          rescue StandardError => e
+            @error = e unless @error
+            raise e
+          end
         end
       end
     end
@@ -28,9 +35,18 @@ module Capybara
 
     def initialize(app)
       @app = app
+      @middleware = Middleware.new(@app)
       @server_thread = nil # supress warnings
     end
 
+    def reset_error!
+      @middleware.error = nil
+    end
+
+    def error
+      @middleware.error
+    end
+
     def host
       Capybara.server_host || "127.0.0.1"
     end
@@ -56,7 +72,7 @@ module Capybara
           Capybara::Server.ports[@app.object_id] = @port
 
           @server_thread = Thread.new do
-            Capybara.server.call(Identify.new(@app), @port)
+            Capybara.server.call(@middleware, @port)
           end
 
           Timeout.timeout(60) { @server_thread.join(0.1) until responsive? }

lib/capybara/session.rb

@@ -45,7 +45,7 @@ module Capybara
     ]
     DSL_METHODS = NODE_METHODS + SESSION_METHODS
 
-    attr_reader :mode, :app
+    attr_reader :mode, :app, :server
 
     def initialize(mode, app=nil)
       @mode = mode
@@ -72,6 +72,9 @@ module Capybara
     def reset!
       driver.reset! if @touched
       @touched = false
+      raise @server.error if @server and @server.error
+    ensure
+      @server.reset_error! if @server
     end
     alias_method :cleanup!, :reset!
     alias_method :reset_session!, :reset!

lib/capybara/spec/session.rb

@@ -3,11 +3,32 @@ require 'nokogiri'
 
 Dir[File.dirname(__FILE__)+'/session/*'].each { |group| require group }
 
+module Quietly
+  def silence_stream(stream)
+    old_stream = stream.dup
+    stream.reopen(RbConfig::CONFIG['host_os'] =~ /rmswin|mingw/ ? 'NUL:' : '/dev/null')
+    stream.sync = true
+    yield
+  ensure
+    stream.reopen(old_stream)
+  end
+
+  def quietly
+    silence_stream(STDOUT) do
+      silence_stream(STDERR) do
+        yield
+      end
+    end
+  end
+end
+
 shared_examples_for "session" do
   def extract_results(session)
     YAML.load Nokogiri::HTML(session.body).xpath("//pre[@id='results']").first.text.lstrip
   end
 
+  include Quietly
+
   after do
     @session.reset_session!
   end
@@ -82,6 +103,15 @@ shared_examples_for "session" do
       @session.body.should_not include('This is a test')
       @session.should have_no_selector('.//h1')
     end
+
+    it "raises any errors caught inside the server" do
+      expect do
+        quietly { @session.visit("/error") }
+        @session.reset_session!
+      end.to raise_error(TestApp::TestAppError)
+      @session.visit("/")
+      @session.current_path.should == "/"
+    end
   end
 
   it_should_behave_like "node"

lib/capybara/spec/test_app.rb

@@ -3,8 +3,12 @@ require 'rack'
 require 'yaml'
 
 class TestApp < Sinatra::Base
+  class TestAppError < StandardError; end
+
   set :root, File.dirname(__FILE__)
   set :static, true
+  set :raise_errors, true
+  set :show_exceptions, false
 
   # Also check lib/capybara/spec/views/*.erb for pages not listed here
 
@@ -114,6 +118,10 @@ class TestApp < Sinatra::Base
     redirect '/get_header'
   end
 
+  get '/error' do
+    raise TestAppError, "some error"
+  end
+
   get '/:view' do |view|
     erb view.to_sym
   end