fix timeout test

lib/faraday/adapter/rack.rb

@@ -16,14 +16,16 @@ module Faraday
     #     conn.adapter :rack, MyRackApp
     #   end
     class Rack < Faraday::Adapter
-      dependency 'rack/test'
+      dependency do
+        require 'rack/test'
 
-      begin
-        require 'system_timer' if RUBY_VERSION < '1.9'
-      rescue LoadError
-        warn "Faraday: you may want to install system_timer for reliable timeouts"
-      ensure
-        SystemTimer = Timeout unless defined? ::SystemTimer
+        begin
+          require 'system_timer' if RUBY_VERSION < '1.9'
+        rescue LoadError
+          warn "Faraday: you may want to install system_timer for reliable timeouts"
+        ensure
+          SystemTimer = Timeout unless defined? ::SystemTimer
+        end
       end
 
       # not prefixed with "HTTP_"
@@ -50,7 +52,7 @@ module Faraday
 
         timeout  = env[:request][:timeout] || env[:request][:open_timeout]
         response = if timeout
-          SystemTimer.timeout(timeout) { execute_request(env, rack_env) }
+          SystemTimer.timeout(timeout, Faraday::Error::TimeoutError) { execute_request(env, rack_env) }
         else
           execute_request(env, rack_env)
         end

test/adapters/rack_test.rb

@@ -17,17 +17,9 @@ module Adapters
     # not using shared test because error is swallowed by Sinatra
     def test_timeout
       conn = create_connection(:request => {:timeout => 1, :open_timeout => 1})
-      err = assert_raise { conn.get '/slow' }
-
-      case err
-      when Faraday::Error::ClientError
-        # happens on Mac OS
-        assert_include err.response[:body], 'execution expired'
-      else
-        # happens on Travis
-        assert_instance_of Timeout::Error, err
+      assert_raise Faraday::Error::ClientError do
+        conn.get '/slow'
       end
     end
-
   end
 end