allow configuring the errors which will be raised by the server

lib/capybara.rb

@@ -22,7 +22,7 @@ module Capybara
     attr_accessor :asset_host, :app_host, :run_server, :default_host, :always_include_port
     attr_accessor :server_port, :exact, :match, :exact_options, :visible_text_only
     attr_accessor :default_selector, :default_wait_time, :ignore_hidden_elements
-    attr_accessor :save_and_open_page_path, :automatic_reload, :raise_server_errors
+    attr_accessor :save_and_open_page_path, :automatic_reload, :raise_server_errors, :server_errors
     attr_writer :default_driver, :current_driver, :javascript_driver, :session_name, :server_host
     attr_accessor :app
 
@@ -135,7 +135,7 @@ module Capybara
     ##
     #
     # Wraps the given string, which should contain an HTML document or fragment
-    # in a {Capybara::Node::Simple} which exposes all {Capybara::Node::Matchers}, 
+    # in a {Capybara::Node::Simple} which exposes all {Capybara::Node::Matchers},
     # {Capybara::Node::Finders} and {Capybara::Node::DocumentMatchers}. This allows you to query
     # any string containing HTML in the exact same way you would query the current document in a Capybara
     # session. For example:
@@ -365,6 +365,7 @@ Capybara.configure do |config|
   config.match = :smart
   config.exact = false
   config.raise_server_errors = true
+  config.server_errors = [StandardError]
   config.visible_text_only = false
 end
 

lib/capybara/server.rb

@@ -17,7 +17,7 @@ module Capybara
         else
           begin
             @app.call(env)
-          rescue StandardError => e
+          rescue *Capybara.server_errors => e
             @error = e unless @error
             raise e
           end

lib/capybara/spec/session/reset_session_spec.rb

@@ -37,7 +37,7 @@ Capybara::SpecHelper.spec '#reset_session!' do
     expect(@session).to have_no_selector :xpath, "/html/body/*", wait: false
   end
 
-  it "raises any errors caught inside the server", :requires => [:server] do
+  it "raises any standard errors caught inside the server", :requires => [:server] do
     quietly { @session.visit("/error") }
     expect do
       @session.reset_session!
@@ -46,6 +46,23 @@ Capybara::SpecHelper.spec '#reset_session!' do
     expect(@session.current_path).to eq("/")
   end
 
+  it "raises configured errors caught inside the server", :requires => [:server] do
+    prev_errors = Capybara.server_errors
+
+    Capybara.server_errors = [LoadError]
+    quietly { @session.visit("/error") }
+    expect do
+      @session.reset_session!
+    end.not_to raise_error
+
+    quietly { @session.visit("/load_error") }
+    expect do
+      @session.reset_session!
+    end.to raise_error(LoadError)
+
+    Capybara.server_errors = prev_errors
+  end
+
   it "ignores server errors when `Capybara.raise_server_errors = false`", :requires => [:server] do
     Capybara.raise_server_errors = false
     quietly { @session.visit("/error") }

lib/capybara/spec/test_app.rb

@@ -123,6 +123,10 @@ class TestApp < Sinatra::Base
     raise TestAppError, "some error"
   end
 
+  get '/load_error' do
+    raise LoadError
+  end
+
   get '/:view' do |view|
     erb view.to_sym
   end