From e832b18cf00043c8f3af875dea766342f82f8038 Mon Sep 17 00:00:00 2001
From: mesmerize <aichernovmail@gmail.com>
Date: Wed, 29 Sep 2021 20:15:31 +0200
Subject: [PATCH] singleton

---
 lib/product.rb             |  5 +++++
 lib/products_controller.rb | 17 +++++++++++++++++
 spec/anything_spec.rb      |  4 ++++
 3 files changed, 26 insertions(+)
 create mode 100644 lib/product.rb
 create mode 100644 lib/products_controller.rb

diff --git a/lib/product.rb b/lib/product.rb
new file mode 100644
index 0000000..56e8c1c
--- /dev/null
+++ b/lib/product.rb
@@ -0,0 +1,5 @@
+class Product
+  def initialize(type)
+    @type = type
+  end
+end
diff --git a/lib/products_controller.rb b/lib/products_controller.rb
new file mode 100644
index 0000000..8841094
--- /dev/null
+++ b/lib/products_controller.rb
@@ -0,0 +1,17 @@
+class ProductsController
+  # include Singleton - right way to do that
+
+  @instance = new
+
+  private_class_method :new
+
+  attr_accessor :product
+
+  def self.instance
+    @instance
+  end
+
+  def show
+    @product = PRODUCT
+  end
+end
diff --git a/spec/anything_spec.rb b/spec/anything_spec.rb
index e39e005..d792474 100644
--- a/spec/anything_spec.rb
+++ b/spec/anything_spec.rb
@@ -8,11 +8,15 @@
 
 describe ProductsController do
   it 'cannot be instantiated via :new' do
+    expect{ ProductsController.new }.to raise_error NoMethodError
   end
 
   it 'can be instantiated only once' do
+    expect(ProductsController.instance.object_id).to eq(ProductsController.instance.object_id)
   end
 
   it 'does some work' do
+    ProductsController.instance.show
+    expect(ProductsController.instance.product).to be(PRODUCT)
   end
 end