Unable to call Ruby mixin instance method from RSpec - ruby

Question

Objective:
I want to run a basic RSpec unit test on an instance method of a mixin (module) named Debug. Below are the file contents of the Debug mixin:
Mixin File: ./mixins/debug.rb
module Debug
public
def class_info?
"#{self.class.name}"
end
end
Validate Debug mixin instance methods accessible from RSpec:
When I run irb and include the Debug mixin with commands require_relative './mixins/debug.rb' and include Debug, and then call Debug.class_info? it successfully returns "Module"
Then if I run rspec with the following RSpec unit test to confirm that the RSpec context can access the instance methods of the mixin, the test successfully passes:
RSpec Unit Test Setup #1: ./spec/mixins/debug_spec.rb
require_relative '../../mixins/debug.rb'
RSpec.describe Debug, "#class_info?" do
include Debug
before(:each) do
#class_info_instance_method = Debug.instance_methods[0].to_s
end
context "with mixins" do
it "has class info instance method" do
expect(#class_info_instance_method).to eq "class_info?"
end
end
end
Problem when calling Debug mixin instance method from RSpec:
Lastly, I change the RSpec unit test to be as follows, so instead it actually calls the class_info? instance method of the Debug mixin:
RSpec Unit Test Setup #2: ./spec/mixins/debug_spec.rb
require_relative '../../mixins/debug.rb'
RSpec.describe Debug, "#class_info?" do
include Debug
before(:each) do
#class_info = Debug.class_info?
end
context "with mixins" do
it "shows class info" do
expect(#class_info).to eq "Module"
end
end
end
But now when I run rspec from the command line, why does it return the following error? (Note: even though in the previous RSpec Unit Test Setup #1 that was entirely similar I checked I could successfully access this Debug mixin instance method)
1) Debug#class_info? with mixins shows class info
Failure/Error: #class_info = Debug.class_info?
NoMethodError:
undefined method `class_info?' for Debug:Module
Note: I have shared the above code in my RubyTest GitHub repo.
Setup and References:
My System:
Ruby: ruby 2.3.0p0 (ruby -v)
RSpec: 3.5.4 (rspec -v)
References:
Applying example from Mixins chapter of Programming Ruby book

Answer 1

When you include a module, the methods become instance methods in the included class. Debug.class_info? doesn't work because there is no class method class_info?. I'm also not sure that the way you've included the module in your test is the best way to do it. Would something like this work?
require_relative '../../mixins/debug.rb'
class TestClass
include Debug
end
RSpec.describe Debug, "#class_info?" do
let(:test_instance) { TestClass.new }
context "with mixins" do
it "shows class info" do
expect(test_instance.class_info?).to eq "TestClass"
end
end
end