Moving following logic to a policy class

abhirao · steveklabnik · commit 5c5276b31810 · 2011-10-15T14:27:12.000-04:00
Backed up by spec
diff --git a/app/models/following_policy.rb b/app/models/following_policy.rb
@@ -0,0 +1,18 @@
+class FollowingPolicy
+  def initialize(follower, target)
+    @follower = follower
+    @target = target
+  end
+  
+  def can_follow?
+    !following_self? && !already_following?
+  end
+  
+  def already_following?
+    @follower.following?(@target)
+  end  
+  
+  def following_self?
+    @follower == @target
+  end
+end
diff --git a/spec/following_policy_spec.rb b/spec/following_policy_spec.rb
@@ -0,0 +1,26 @@
+require_relative '../app/models/following_policy'
+
+describe FollowingPolicy do
+  before(:each) do 
+    @followed = stub()
+    @follower = stub()
+  end
+  
+  it 'can follow another' do
+    @follower.should_receive(:following?).with(@followed).and_return(false)
+    policy = FollowingPolicy.new(@follower, @followed)
+    policy.can_follow?.should be_true
+  end
+  
+  it "cannot follow self" do
+    policy = FollowingPolicy.new(@follower, @follower)
+    policy.can_follow?.should be_false
+  end
+  
+  it "cannot follow twice" do
+    @follower.should_receive(:following?).with(@followed).and_return(true)
+    policy = FollowingPolicy.new(@follower,@followed)
+    policy.can_follow?.should be_false
+  end
+  
+end
