do not raise NotFound exceptions, even if show_exceptions is enabled, fixes #324

lib/sinatra/base.rb

@@ -801,8 +801,11 @@ module Sinatra
     def handle_exception!(boom)
       @env['sinatra.error'] = boom
       status boom.respond_to?(:code) ? Integer(boom.code) : 500
-      dump_errors! boom if settings.dump_errors? and server_error?
-      raise boom if settings.show_exceptions? and settings.show_exceptions != :after_handler
+
+      if server_error?
+        dump_errors! boom if settings.dump_errors?
+        raise boom if settings.show_exceptions? and settings.show_exceptions != :after_handler
+      end
 
       if not_found?
         headers['X-Cascade'] = 'pass'

test/mapped_error_test.rb

@@ -112,12 +112,7 @@ class MappedErrorTest < Test::Unit::TestCase
     end
 
     it "never raises Sinatra::NotFound beyond the application" do
-      mock_app {
-        set :raise_errors, true
-        get '/' do
-          raise Sinatra::NotFound
-        end
-      }
+      mock_app(Sinatra::Application) { get('/') { raise Sinatra::NotFound }}
       assert_nothing_raised { get '/' }
       assert_equal 404, status
     end