Add Mock Method Chain Calls With RSpec as a ruby til

Author: jbranchaud

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_822 TILs and counting..._
+_823 TILs and counting..._
 
 ---
 
@@ -648,6 +648,7 @@ _822 TILs and counting..._
 - [Last Raised Exception In The Call Stack](ruby/last-raised-exception-in-the-call-stack.md)
 - [Limit Split](ruby/limit-split.md)
 - [Listing Local Variables](ruby/listing-local-variables.md)
+- [Mock Method Chain Calls With RSpec](ruby/mock-method-chain-calls-with-rspec.md)
 - [Mocking Requests With Partial URIs Using Regex](ruby/mocking-requests-with-partial-uris-using-regex.md)
 - [Navigate Back In The Browser With Capybara](ruby/navigate-back-in-the-browser-with-capybara.md)
 - [Next And Previous Floats](ruby/next-and-previous-floats.md)

ruby/mock-method-chain-calls-with-rspec.md

@@ -0,0 +1,31 @@
+# Mock Method Chain Calls With RSpec
+
+Generally with RSpec you mock one method call at a time:
+
+```ruby
+allow(User).to receive(:new).and_return(true)
+```
+
+Sometimes you are dealing with code that involves a chain of method calls.
+
+```ruby
+User
+  .new
+  .approve
+  .send_welcome_email
+```
+
+If it becomes unreasonable to mock out each individual method, you can instead
+mock out the chain of calls.
+
+```ruby
+allow(User).to receive_message_chain('new.approve.send_welcome_email')
+```
+
+Alternatively, you can write this as:
+
+```ruby
+allow(User).to receive_message_chain(:new, :approve, :send_welcome_email)
+```
+
+[source](https://relishapp.com/rspec/rspec-mocks/docs/working-with-legacy-code/message-chains)