3 files changed, 12 insertions, 5 deletions
diff --git a/guides/source/active_model_basics.md b/guides/source/active_model_basics.md
index fe2501bd87..8f8256c983 100644
--- a/guides/source/active_model_basics.md
+++ b/guides/source/active_model_basics.md
@@ -8,10 +8,10 @@ classes. Active Model allows for Action Pack helpers to interact with
 plain Ruby objects. Active Model also helps build custom ORMs for use
 outside of the Rails framework.
 
-After reading this guide, you will know: 
+After reading this guide, you will know:
 
 * How an Active Record model behaves.
-* How Callbacks and validations work. 
+* How Callbacks and validations work.
 * How serializers work.
 * The Rails internationalization (i18n) framework.
 
@@ -428,7 +428,7 @@ the Active Model API.
     class PersonTest < ActiveSupport::TestCase
       include ActiveModel::Lint::Tests
 
-      def setup
+      setup do
         @model = Person.new
       end
     end
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index 556b5ede3c..f6fc255c24 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -248,6 +248,13 @@ end
 @person.try { |p| "#{p.first_name} #{p.last_name}" }
 ```
 
+Note that `try` will swallow no-method errors, returning nil instead. If you want to protect against typos, use `try!` instead:
+
+```ruby
+@number.try(:nest)  # => nil
+@number.try!(:nest) # NoMethodError: undefined method `nest' for 1:Fixnum
+```
+
 NOTE: Defined in `active_support/core_ext/object/try.rb`.
 
 ### `class_eval(*args, &block)`
diff --git a/guides/source/testing.md b/guides/source/testing.md
index a07772036b..2f941a8280 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -908,12 +908,12 @@ require 'test_helper'
 
 class ArticlesControllerTest < ActionController::TestCase
   # called before every single test
-  def setup
+  setup do
     @article = articles(:one)
   end
 
   # called after every single test
-  def teardown
+  teardown do
     # when controller is using cache it may be a good idea to reset it afterwards
     Rails.cache.clear
   end