template method

lib/generator.rb

@@ -1,31 +1,19 @@
 module Newsletter
   class Generator
-    def initialize(format)
-      @format = format
-    end
-
     def render
-      <<~HTML
+      <<~HTMLORMARKDOWN
         #{header}
 
         #{body}
-      HTML
+      HTMLORMARKDOWN
     end
 
     def header
-      if @format == :html
-        '<h1>header</h1>'
-      elsif @format == :markdown
-        '# Header'
-      end
+      raise NotImplementedError
     end
 
     def body
-      if @format == :html
-        '<p>body</p>'
-      elsif @format == :markdown
-        'body'
-      end
+      raise NotImplementedError
     end
   end
 end

lib/generators/html.rb

@@ -0,0 +1,13 @@
+module Newsletter
+  module Generators
+    class Html < Newsletter::Generator
+      def header
+        '<h1>header</h1>'
+      end
+
+      def body
+        '<p>body</p>'
+      end
+    end
+  end
+end

lib/generators/markdown.rb

@@ -0,0 +1,13 @@
+module Newsletter
+  module Generators
+    class Markdown < Newsletter::Generator
+      def header
+        '# Header'
+      end
+
+      def body
+        'body'
+      end
+    end
+  end
+end

spec/anything_spec.rb

@@ -1,28 +1,40 @@
 require 'spec_hepler'
 require_relative '../lib/generator'
+require_relative '../lib/generators/html'
+require_relative '../lib/generators/markdown'
 
-describe Newsletter::Generator do
-  context 'when HTML' do
-    let(:newsletter) do
-      File.read(
-        File.expand_path('fixtures/newsletter.html', File.dirname(__FILE__))
-      )
-    end
+module Newsletter
+  describe Generator do
+    context 'when HTML' do
+      let(:newsletter) do
+        File.read(
+          File.expand_path('fixtures/newsletter.html', File.dirname(__FILE__))
+        )
+      end
 
-    it 'generates HTML' do
-      expect(described_class.new(:html).render).to include(newsletter)
+      it 'generates HTML' do
+        expect(Generators::Html.new.render).to include(newsletter)
+      end
     end
-  end
 
-  context 'when markdown' do
-    let(:newsletter) do
-      File.read(
-        File.expand_path('fixtures/newsletter.markdown', File.dirname(__FILE__))
-      )
+    context 'when markdown' do
+      let(:newsletter) do
+        File.read(
+          File.expand_path('fixtures/newsletter.markdown', File.dirname(__FILE__))
+        )
+      end
+
+      it 'generates markdown' do
+        expect(Newsletter::Generators::Markdown.new.render).to include(newsletter)
+      end
     end
 
-    it 'generates markdown' do
-      expect(described_class.new(:markdown).render).to include(newsletter)
+    context 'when we calling the base class' do
+      it 'Template method requires base class to ba abstract!!!' do
+        expect{ Generator.new.render }.to raise_error(NotImplementedError)
+        expect{ Generator.new.header }.to raise_error(NotImplementedError)
+        expect{ Generator.new.body }.to raise_error(NotImplementedError)
+      end
     end
   end
 end