Separate Query from Modifier.

separate-query-from-modifier/lib/after.rb

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+class Post
+  attr_reader :id, :title, :body, :created_at
+  def initialize id, title, body, created_at
+    @id         = id
+    @title      = title
+    @body       = body
+    @created_at = created_at
+    @published = false
+  end
+
+  def self.find id
+    # database operation to retrieve data. We'll simulate it for now.
+    post = POSTS.find { |post| post.id == id }
+  end
+
+  def self.unpublished
+    return POSTS.count { |post| !post.published? }
+  end
+
+  def publish
+    @published = true
+  end
+
+  def unpublish
+    @published = false
+  end
+
+  def published?
+    @published
+  end
+
+end
+
+### Sample data
+
+POSTS = [
+  Post.new(
+    1,
+    "Introduce Null Object Pattern",
+    "Post body should be here",
+    Time.new(2013,01,25)
+  ),
+  Post.new(
+    2,
+    "Introduce Assertion",
+    "Post body should be here",
+    Time.new(2012,02,26)
+  ),
+  Post.new(
+    3,
+    "Extract Method",
+    "Post body should be here",
+    Time.new(2014,01,27)
+  ),
+  Post.new(
+    4,
+    "Replace Type Code with Polymorphism",
+    "Post body should be here",
+    Time.new(2015,10,12)
+  )
+]
+

separate-query-from-modifier/lib/before.rb

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+class Post
+  attr_reader :id, :title, :body, :created_at
+  def initialize id, title, body, created_at
+    @id         = id
+    @title      = title
+    @body       = body
+    @created_at = created_at
+    @published = false
+  end
+
+  def self.find id
+    # database operation to retrieve data. We'll simulate it for now.
+    post = POSTS.find { |post| post.id == id }
+  end
+
+  def publish
+    @published = true
+    return POSTS.count { |post| !post.published? }
+  end
+
+  def unpublish
+    @published = false
+  end
+
+  def published?
+    @published
+  end
+
+end
+
+### Sample data
+
+POSTS = [
+  Post.new(
+    1,
+    "Introduce Null Object Pattern",
+    "Post body should be here",
+    Time.new(2013,01,25)
+  ),
+  Post.new(
+    2,
+    "Introduce Assertion",
+    "Post body should be here",
+    Time.new(2012,02,26)
+  ),
+  Post.new(
+    3,
+    "Extract Method",
+    "Post body should be here",
+    Time.new(2014,01,27)
+  ),
+  Post.new(
+    4,
+    "Replace Type Code with Polymorphism",
+    "Post body should be here",
+    Time.new(2015,10,12)
+  )
+]
+

separate-query-from-modifier/test/test.rb

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+require 'minitest/autorun'
+require 'minitest/spec'
+
+require 'before' if ENV["BEFORE"]
+require 'after' unless ENV["BEFORE"]
+
+describe Post do
+
+  before :each do
+    POSTS.each { |post| post.unpublish }
+  end
+
+  if ENV["BEFORE"]
+    it "is publishable and retrieves all unpublished posts count" do
+      post = Post.find(1)
+      post.publish.must_equal 3
+    end
+
+  else # AFTER
+
+    it "is publishable" do
+      post = Post.find(1)
+      post.publish.must_equal true
+    end
+
+    it "retrieves all unpublished posts count" do
+      Post.unpublished.must_equal 4
+    end
+
+  end
+end