Cukes.

features/animal.feature

@@ -1 +1,10 @@
-#Create your feature here
+Feature: Animal
+  As a cat, I should have a name, type, and age
+  As a cat under 3 years old
+  I am not old
+
+  Scenario: Cat
+    Given an animal
+    Then it has a name 'Elsa'
+    And it has an age of 2
+    And it is not old

features/step_definitions/animal_steps.rb

@@ -1 +1,15 @@
-#Delete this comment, here is where you should write your step defs
+Given(/^an animal$/) do
+  @animal = Animal.new('Elsa', 'cat', 2)
+end
+
+Then(/^it has a name 'Elsa'$/) do
+  expect(@animal.name).to eq('Elsa')
+end
+
+Then(/^it has an age of (\d+)$/) do |arg1|
+  expect(@animal.age).to eq(2)
+end
+
+Then(/^it is not old$/) do
+  expect(@animal.old?).to be(false)
+end