Rewrite ActiveModel::Lint as a simple TU mixin

activemodel/lib/active_model/lint.rb

 # You can test whether an object is compliant with the ActiveModel API by
-# calling ActiveModel::Lint.test(object). It will emit a Test::Unit
-# output that tells you whether your object is fully compliant, or if not,
+# including ActiveModel::Lint::Tests in your TestCase. It will included
+# tests that tell you whether your object is fully compliant, or if not,
 # which aspects of the API are not implemented.
 #
 # These tests do not attempt to determine the semantic correctness of the
@@ -12,36 +12,15 @@
 # call to to_model. It is perfectly fine for to_model to return self.
 module ActiveModel
   module Lint
-    def self.test(object, verbosity = 2, output = STDOUT)
-      require "test/unit"
-      require "test/unit/ui/console/testrunner"
-
-      test_class = Class.new(::Test::Unit::TestCase) do
-        include Test
-
-        define_method(:setup) do
-          assert object.respond_to?(:to_model), "The object should respond_to :to_model"
-          @object = object.to_model
-          super
-        end
-      end
-
-      ::Test::Unit::UI::Console::TestRunner.new(test_class, verbosity, output).start
-    end
-
-    module Test
-      def assert_boolean(name, result)
-        assert result == true || result == false, "#{name} should be a boolean"
-      end
-
+    module Tests
       # valid?
       # ------
       #
       # Returns a boolean that specifies whether the object is in a valid or invalid
       # state.
       def test_valid?
-        assert @object.respond_to?(:valid?), "The model should respond to valid?"
-        assert_boolean "valid?", @object.valid?
+        assert model.respond_to?(:valid?), "The model should respond to valid?"
+        assert_boolean model.valid?, "valid?"
       end
 
       # new_record?
@@ -53,13 +32,13 @@ def test_valid?
       # collection. If it is persisted, a form for the object will put PUTed to the
       # URL for the object.
       def test_new_record?
-        assert @object.respond_to?(:new_record?), "The model should respond to new_record?"
-        assert_boolean "new_record?", @object.new_record?
+        assert model.respond_to?(:new_record?), "The model should respond to new_record?"
+        assert_boolean model.new_record?, "new_record?"
       end
 
       def test_destroyed?
-        assert @object.respond_to?(:destroyed?), "The model should respond to destroyed?"
-        assert_boolean "destroyed?", @object.destroyed?
+        assert model.respond_to?(:destroyed?), "The model should respond to destroyed?"
+        assert_boolean model.destroyed?, "destroyed?"
       end
 
       # errors
@@ -67,29 +46,32 @@ def test_destroyed?
       #
       # Returns an object that has :[] and :full_messages defined on it. See below
       # for more details.
-      def setup
-        assert @object.respond_to?(:errors), "The model should respond to errors"
-        @errors = @object.errors
+
+      # Returns an Array of Strings that are the errors for the attribute in
+      # question. If localization is used, the Strings should be localized
+      # for the current locale. If no error is present, this method should
+      # return an empty Array.
+      def test_errors_aref
+        assert model.respond_to?(:errors), "The model should respond to errors"
+        assert model.errors[:hello].is_a?(Array), "errors#[] should return an Array"
       end
 
-      # This module tests the #errors object
-      module Errors
-        # Returns an Array of Strings that are the errors for the attribute in
-        # question. If localization is used, the Strings should be localized
-        # for the current locale. If no error is present, this method should
-        # return an empty Array.
-        def test_errors_aref
-          assert @errors[:hello].is_a?(Array), "errors#[] should return an Array"
-        end
+      # Returns an Array of all error messages for the object. Each message
+      # should contain information about the field, if applicable.
+      def test_errors_full_messages
+        assert model.respond_to?(:errors), "The model should respond to errors"
+        assert model.errors.full_messages.is_a?(Array), "errors#full_messages should return an Array"
+      end
 
-        # Returns an Array of all error messages for the object. Each message
-        # should contain information about the field, if applicable.
-        def test_errors_full_messages
-          assert @errors.full_messages.is_a?(Array), "errors#full_messages should return an Array"
+      private
+        def model
+          assert @model.respond_to?(:to_model), "The object should respond_to to_model"
+          @model.to_model
         end
-      end
 
-      include Errors
+        def assert_boolean(result, name)
+          assert result == true || result == false, "#{name} should be a boolean"
+        end
     end
   end
 end

activemodel/test/cases/lint_test.rb

 require "cases/helper"
 
-class TestLint < ActiveModel::TestCase
-  class CompliantObject
+class LintTest < ActiveModel::TestCase
+  include ActiveModel::Lint::Tests
+
+  class CompliantModel
     def to_model
       self
     end
-    
+
     def valid?()      true end
     def new_record?() true end
     def destroyed?()  true end
-    
+
     def errors
       obj = Object.new
       def obj.[](key)         [] end
@@ -17,34 +19,8 @@ def obj.full_messages() [] end
       obj
     end
   end
-  
-  def assert_output(object, failures, errors, *test_names)
-    ActiveModel::Lint.test(object, 3, output = StringIO.new)
-    regex =  %r{#{failures} failures, #{errors} errors}
-    assert_match regex, output.string
-    
-    test_names.each do |test_name|
-      assert_match test_name, output.string
-    end
-  end
-  
-  def test_valid
-    assert_output(CompliantObject.new, 0, 0, /test_valid/)
-  end
-  
-  def test_new_record
-    assert_output(CompliantObject.new, 0, 0, /test_new_record?/)
-  end
-  
-  def test_destroyed
-    assert_output(CompliantObject.new, 0, 0, /test_destroyed/)
-  end
-  
-  def test_errors_aref
-    assert_output(CompliantObject.new, 0, 0, /test_errors_aref/)
-  end
 
-  def test_errors_full_messages
-    assert_output(CompliantObject.new, 0, 0, /test_errors_aref/)
+  def setup
+    @model = CompliantModel.new
   end
 end