chriswright47 · August 14, 2015 18:42 · Aug 14, 2015
diff --git a/checked_attr_challenge.rb b/checked_attr_challenge.rb
@@ -0,0 +1,43 @@
+# CheckedAttributes Challenge
+module CheckedAttributes
+  class ValidationError < StandardError; end
+
+  def self.included(base)
+    base.extend(self)
+  end
+
+  def attr_checked attribute, &block
+    attr_reader attribute
+
+    define_method "#{attribute}=" do |value|
+      raise ValidationError unless block.call(value)
+
+      instance_variable_set("@#{attribute}", value)
+    end
+  end
+end
+
+class Person
+  include CheckedAttributes
+
+  attr_checked :age do |v|
+    v >= 18
+  end
+end
+
+require "minitest/autorun"
+
+describe "CheckedAttributes" do
+  before do
+    @subject = Person.new
+  end
+
+  it "raises an error if the validation fails" do
+    @subject .age = 18
+    assert_equal @subject .age, 18
+  end
+
+  it "raises an error if the validation fails" do
+    assert_raises(CheckedAttributes::ValidationError) { @subject.age = 12 }
+  end
+end