test/test_observer.rb

   1 # frozen_string_literal: true
   2 require 'test/unit'
   3 require 'observer'
   4
   5 class TestObserver < Test::Unit::TestCase
   6   class TestObservable
   7     include Observable
   8
   9     def notify(*args)
  10       changed
  11       notify_observers(*args)
  12     end
  13   end
  14
  15   class TestWatcher
  16     def initialize(observable)
  17       @notifications = []
  18       observable.add_observer(self)
  19     end
  20
  21     attr_reader :notifications
  22
  23     def update(*args)
  24       @notifications << args
  25     end
  26   end
  27
  28   def test_observers
  29     observable = TestObservable.new
  30
  31     assert_equal(0, observable.count_observers)
  32
  33     watcher1 = TestWatcher.new(observable)
  34
  35     assert_equal(1, observable.count_observers)
  36
  37     observable.notify("test", 123)
  38
  39     watcher2 = TestWatcher.new(observable)
  40
  41     assert_equal(2, observable.count_observers)
  42
  43     observable.notify(42)
  44
  45     assert_equal([["test", 123], [42]], watcher1.notifications)
  46     assert_equal([[42]], watcher2.notifications)
  47
  48     observable.delete_observer(watcher1)
  49
  50     assert_equal(1, observable.count_observers)
  51
  52     observable.notify(:cats)
  53
  54     assert_equal([["test", 123], [42]], watcher1.notifications)
  55     assert_equal([[42], [:cats]], watcher2.notifications)
  56
  57     observable.delete_observers
  58
  59     assert_equal(0, observable.count_observers)
  60
  61     observable.notify("nope")
  62
  63     assert_equal([["test", 123], [42]], watcher1.notifications)
  64     assert_equal([[42], [:cats]], watcher2.notifications)
  65   end
  66 end