Do not display other behaviour if the email address does not exist

app/controllers/public/unsubscribes_controller.rb

@@ -11,14 +11,14 @@ module Public
 
     def create
       @user = get_user
-      @user.admin_unsubscribe!
+      @user.admin_unsubscribe! if @user
       redirect_to new_user_session_path, notice: 'You have been unsubscribed'
     end
 
     protected
     def get_user
       @email = "#{params[:email]}.#{params[:format]}"
-      User.where(email: @email).first!
+      User.where(email: @email).first
     end
   end
 end
\ No newline at end of file

spec/controllers/public/unsubscribes_controller_spec.rb

@@ -9,6 +9,12 @@ describe Public::UnsubscribesController do
 
       assert_response :success
     end
+
+    it "behaves the same if email address isn't known in the system" do
+      get :show, email: 'i@dont_exists', format: 'com'
+
+      assert_response :success
+    end
   end
 
   describe "create" do
@@ -17,5 +23,12 @@ describe Public::UnsubscribesController do
 
       assert user.reload.admin_email_unsubscribed_at
     end
+
+    # Don't tell if the email does not exists
+    it "behaves the same if email address isn't known in the system" do
+      post :create, email: 'i@dont_exists', format: 'com'
+
+      assert_response :redirect
+    end
   end
 end