rails--rails/activemodel/test/observing_test.rb

require 'test_helper'

class ObservedModel < ActiveModel::Base
  class Observer
  end
end

class FooObserver < ActiveModel::Observer
  class << self
    public :new
  end
  
  attr_accessor :stub

  def on_spec(record)
    stub.event_with(record) if stub
  end
end

class Foo < ActiveModel::Base
end

class ObservingTest < ActiveModel::TestCase
  def setup
    ObservedModel.observers.clear
  end

  test "initializes model with no cached observers" do
    assert ObservedModel.observers.empty?, "Not empty: #{ObservedModel.observers.inspect}"
  end
  
  test "stores cached observers in an array" do
    ObservedModel.observers << :foo
    assert ObservedModel.observers.include?(:foo), ":foo not in #{ObservedModel.observers.inspect}"
  end
  
  test "flattens array of assigned cached observers" do
    ObservedModel.observers = [[:foo], :bar]
    assert ObservedModel.observers.include?(:foo), ":foo not in #{ObservedModel.observers.inspect}"
    assert ObservedModel.observers.include?(:bar), ":bar not in #{ObservedModel.observers.inspect}"
  end

  test "instantiates observer names passed as strings" do
    ObservedModel.observers << 'foo_observer'
    FooObserver.expects(:instance)
    ObservedModel.instantiate_observers
  end

  test "instantiates observer names passed as symbols" do
    ObservedModel.observers << :foo_observer
    FooObserver.expects(:instance)
    ObservedModel.instantiate_observers
  end

  test "instantiates observer classes" do
    ObservedModel.observers << ObservedModel::Observer
    ObservedModel::Observer.expects(:instance)
    ObservedModel.instantiate_observers
  end
  
  test "passes observers to subclasses" do
    FooObserver.instance
    bar = Class.new(Foo)
    assert_equal Foo.count_observers, bar.count_observers
  end
end
  
class ObserverTest < ActiveModel::TestCase
  def setup
    ObservedModel.observers = :foo_observer
    FooObserver.models = nil
  end

  test "guesses implicit observable model name" do
    assert_equal 'Foo', FooObserver.observed_class_name
  end

  test "tracks implicit observable models" do
    instance = FooObserver.new
    assert  instance.send(:observed_classes).include?(Foo), "Foo not in #{instance.send(:observed_classes).inspect}"
    assert !instance.send(:observed_classes).include?(ObservedModel), "ObservedModel in #{instance.send(:observed_classes).inspect}"
  end
  
  test "tracks explicit observed model class" do
    old_instance = FooObserver.new
    assert !old_instance.send(:observed_classes).include?(ObservedModel), "ObservedModel in #{old_instance.send(:observed_classes).inspect}"
    FooObserver.observe ObservedModel
    instance = FooObserver.new
    assert instance.send(:observed_classes).include?(ObservedModel), "ObservedModel not in #{instance.send(:observed_classes).inspect}"
  end
  
  test "tracks explicit observed model as string" do
    old_instance = FooObserver.new
    assert !old_instance.send(:observed_classes).include?(ObservedModel), "ObservedModel in #{old_instance.send(:observed_classes).inspect}"
    FooObserver.observe 'observed_model'
    instance = FooObserver.new
    assert instance.send(:observed_classes).include?(ObservedModel), "ObservedModel not in #{instance.send(:observed_classes).inspect}"
  end
  
  test "tracks explicit observed model as symbol" do
    old_instance = FooObserver.new
    assert !old_instance.send(:observed_classes).include?(ObservedModel), "ObservedModel in #{old_instance.send(:observed_classes).inspect}"
    FooObserver.observe :observed_model
    instance = FooObserver.new
    assert instance.send(:observed_classes).include?(ObservedModel), "ObservedModel not in #{instance.send(:observed_classes).inspect}"
  end
  
  test "calls existing observer event" do
    foo = Foo.new
    FooObserver.instance.stub = stub
    FooObserver.instance.stub.expects(:event_with).with(foo)
    Foo.send(:changed)
    Foo.send(:notify_observers, :on_spec, foo)
  end
  
  test "skips nonexistent observer event" do
    foo = Foo.new
    Foo.send(:changed)
    Foo.send(:notify_observers, :whatever, foo)
  end
end