Add tests for product validations

app/models/product.rb

@@ -25,7 +25,7 @@ class Product < ActiveRecord::Base
 
   validates :name, presence: true
   validates :price_cents, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
-  validates :stock, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :stock, presence: true, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
   validates :calories, numericality: { only_integer: true, allow_nil: true, greater_than_or_equal_to: 0 }
   validates_attachment :avatar,
     presence: true,

spec/models/product_spec.rb

@@ -25,4 +25,54 @@ describe Product do
   it 'has a valid factory' do
     expect(@product).to be_valid
   end
+
+  describe 'validations' do
+    it 'name should be present' do
+      @product.name = ''
+      expect(@product).to_not be_valid
+    end
+
+    describe 'price' do
+      it 'should be positive' do
+        @product.price = -5
+        expect(@product).to_not be_valid
+      end
+
+      it 'should be saved correctly' do
+        @product.price = 1.20
+        @product.save
+        expect(@product.reload.price).to eq(1.20)
+        expect(@product.reload.price_cents).to eq(120)
+      end
+    end
+
+    describe 'stock' do
+      it 'should be present' do
+        @product.stock = nil
+        expect(@product).to_not be_valid
+      end
+
+      it 'should be positive' do
+        @product.stock = -5
+        expect(@product).to_not be_valid
+      end
+    end
+
+    describe 'calories' do
+      it 'should not be present' do
+        @product.calories = nil
+        expect(@product).to be_valid
+      end
+
+      it 'should be positive' do
+        @product.calories = -5
+        expect(@product).to_not be_valid
+      end
+    end
+
+    it 'avatar should be present' do
+      @product.avatar = nil
+      expect(@product).to_not be_valid
+    end
+  end
 end