4 files changed, 69 insertions, 4 deletions
diff --git a/guides/source/autoloading_and_reloading_constants.md b/guides/source/autoloading_and_reloading_constants.md
index 2b6d7e4044..5126d87bee 100644
--- a/guides/source/autoloading_and_reloading_constants.md
+++ b/guides/source/autoloading_and_reloading_constants.md
@@ -790,7 +790,7 @@ Constant Reloading
 When `config.cache_classes` is false Rails is able to reload autoloaded
 constants.
 
-For example, in you're in a console session and edit some file behind the
+For example, if you're in a console session and edit some file behind the
 scenes, the code can be reloaded with the `reload!` command:
 
 ```
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 28388e4957..729d1cc661 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -199,7 +199,7 @@ The full set of methods that can be used in this block are as follows:
 Every Rails application comes with a standard set of middleware which it uses in this order in the development environment:
 
 * `ActionDispatch::SSL` forces every request to be under HTTPS protocol. Will be available if `config.force_ssl` is set to `true`. Options passed to this can be configured by using `config.ssl_options`.
-* `ActionDispatch::Static` is used to serve static assets. Disabled if `config.public_file_server.enabled` is `false`. Set `config.static_index` if you need to serve a static directory index file that is not named `index`. For example, to serve `main.html` instead of `index.html` for directory requests, set `config.static_index` to `"main"`.
+* `ActionDispatch::Static` is used to serve static assets. Disabled if `config.public_file_server.enabled` is `false`. Set `config.public_file_server.index_name` if you need to serve a static directory index file that is not named `index`. For example, to serve `main.html` instead of `index.html` for directory requests, set `config.public_file_server.index_name` to `"main"`.
 * `Rack::Lock` wraps the app in mutex so it can only be called by a single thread at a time. Only enabled when `config.cache_classes` is `false`.
 * `ActiveSupport::Cache::Strategy::LocalCache` serves as a basic memory backed cache. This cache is not thread safe and is intended only for serving as a temporary memory cache for a single thread.
 * `Rack::Runtime` sets an `X-Runtime` header, containing the time (in seconds) taken to execute the request.
@@ -1149,3 +1149,25 @@ Disallow: /
 
 To block just specific pages, it's necessary to use a more complex syntax. Learn
 it on the [official documentation](http://www.robotstxt.org/robotstxt.html).
+
+Evented File System Monitor
+---------------------------
+
+If the [listen gem](https://github.com/guard/listen) is loaded Rails uses an
+evented file system monitor to detect changes when `config.cache_classes` is
+false:
+
+```ruby
+group :development do
+  gem 'listen', '~> 3.0.4'
+end
+```
+
+Otherwise, in every request Rails walks the application tree to check if
+anything has changed.
+
+On Linux and Mac OS X no additional gems are needed, but some are required
+[for *BSD](https://github.com/guard/listen#on-bsd) and
+[for Windows](https://github.com/guard/listen#on-windows).
+
+Note that [some setups are unsupported](https://github.com/guard/listen#issues--limitations).
diff --git a/guides/source/engines.md b/guides/source/engines.md
index f961b799f1..359796b1ff 100644
--- a/guides/source/engines.md
+++ b/guides/source/engines.md
@@ -239,6 +239,27 @@ NOTE: The `ApplicationController` class inside an engine is named just like a
 Rails application in order to make it easier for you to convert your
 applications into engines.
 
+NOTE: Because of the way that Ruby does constant lookup you may run into a situation
+where your engine controller is inheriting from the main application controller and
+not your engine's application controller. Ruby is able to resolve the `ApplicationController` constant, and therefore the autoloading mechanism is not triggered. See the section [When Constants Aren't Missed](autoloading_and_reloading_constants.html#when-constants-aren-t-missed) of the [Autoloading and Reloading Constants](autoloading_and_reloading_constants.html) guide for further details. The best way to prevent this from
+happening is to use `require_dependency` to ensure that the engine's application
+controller is loaded. For example:
+
+``` ruby
+# app/controllers/blorgh/articles_controller.rb:
+require_dependency "blorgh/application_controller"
+
+module Blorgh
+  class ArticlesController < ApplicationController
+    ...
+  end
+end
+```
+
+WARNING: Don't use `require` because it will break the automatic reloading of classes
+in the development environment - using `require_dependency` ensures that classes are
+loaded and unloaded in the correct manner.
+
 Lastly, the `app/views` directory contains a `layouts` folder, which contains a
 file at `blorgh/application.html.erb`. This file allows you to specify a layout
 for the engine. If this engine is to be used as a stand-alone engine, then you
diff --git a/guides/source/testing.md b/guides/source/testing.md
index 2f941a8280..f63ea49955 100644
--- a/guides/source/testing.md
+++ b/guides/source/testing.md
@@ -155,7 +155,7 @@ Failed assertion, no message given.
 1 tests, 1 assertions, 1 failures, 0 errors, 0 skips
 ```
 
-In the output, `F` denotes a failure. You can see the corresponding trace shown under `1)` along with the name of the failing test. The next few lines contain the stack trace followed by a message which mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here:
+In the output, `F` denotes a failure. You can see the corresponding trace shown under `1)` along with the name of the failing test. The next few lines contain the stack trace followed by a message that mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here:
 
 ```ruby
 test "should not save article without title" do
@@ -523,7 +523,7 @@ Model tests don't have their own superclass like `ActionMailer::TestCase` instea
 Integration Testing
 -------------------
 
-Integration tests are used to test how various parts of your application interact. They are generally used to test important work flows within your application.
+Integration tests are used to test how various parts of your application interact. They are generally used to test important workflows within your application.
 
 For creating Rails integration tests, we use the 'test/integration' directory for your application. Rails provides a generator to create an integration test skeleton for you.
 
@@ -1232,3 +1232,25 @@ class ProductTest < ActiveJob::TestCase
   end
 end
 ```
+
+Testing Time-Dependent Code
+---------------------------
+
+Rails provides inbuilt helper methods that enable you to assert that your time-sensitve code works as expected.
+
+Here is an example using the [`travel_to`](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html#method-i-travel_to) helper:
+
+```ruby
+# Lets say that a user is eligible for gifting a month after they register.
+user = User.create(name: 'Gaurish', activation_date: Date.new(2004, 10, 24))
+assert_not user.applicable_for_gifting?
+travel_to Date.new(2004, 11, 24) do
+  assert_equal Date.new(2004, 10, 24), user.activation_date # inside the travel_to block `Date.current` is mocked
+  assert user.applicable_for_gifting?
+end
+assert_equal Date.new(2004, 10, 24), user.activation_date # The change was visible only inside the `travel_to` block.
+```
+
+Please see [`ActiveSupport::TimeHelpers` API Documentation](http://api.rubyonrails.org/classes/ActiveSupport/Testing/TimeHelpers.html)
+for in-depth information about the available time helpers.
+