Testing a private module method in RSpec

There are 2 ways to write a test for a private module method:

1. Create an instance of a class that extends the target class, then use it as a double.

obj = Class.new { exted TargetClass }
allow(obj).to receive(:another_method)
obj.send(:private_method)
expect(obj).to have_received(:another_method)

2. Include the target class at the top of the RSpec file, not recommended though.

include TargetClass

...