Add Mock Method Chain Calls With RSpec as a ruby til

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

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+# 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)