done mvp

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    simple_monads (0.1.2)
+    simple_monads (0.1.3)
 
 GEM
   remote: https://rubygems.org/

lib/simple_monads/failure_object.rb

@@ -4,6 +4,7 @@ module SimpleMonads
   # failure object
   class FailureObject
     attr_reader :object
+    alias failure object
 
     def initialize(object)
       @object = object

lib/simple_monads/success_object.rb

@@ -4,6 +4,7 @@ module SimpleMonads
   # success object
   class SuccessObject
     attr_reader :object
+    alias success object
 
     def initialize(object)
       @object = object

lib/simple_monads/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module SimpleMonads
-  VERSION = '0.1.2'
+  VERSION = '0.1.3'
 end

test/lib/simple_monads_test.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+
+class SomeClass
+  include SimpleMonads
+
+  def return_failure
+    Failure({ error: 'text' })
+  end
+
+  def return_success
+    Success(5)
+  end
+end
+
+class SimpleMonadsTest < Minitest::Test
+  def setup
+    @object = SomeClass.new
+  end
+
+  def test_failure
+    result = @object.return_failure
+
+    assert_predicate result, :failure?
+    refute_predicate result, :success?
+
+    assert_equal({ error: 'text' }, result.failure)
+  end
+
+  def test_success
+    result = @object.return_success
+
+    assert_predicate result, :success?
+    refute_predicate result, :failure?
+
+    assert_equal(5, result.success)
+  end
+end

test/test_helper.rb

@@ -3,5 +3,6 @@
 require 'minitest/autorun'
 require 'byebug'
 require 'minitest/reporters'
+require_relative '../lib/simple_monads'
 
 Minitest::Reporters.use!