public void Add_triggers_CollectionChanged()
        {
            var sut = new EventRaisingCollection <Person> (_source);
            NotifyCollectionChangedEventArgs capturedArgs = default;

            void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs args) => capturedArgs = args;

            sut.CollectionChanged += OnCollectionChanged;

            sut.Add(new Person());

            sut.CollectionChanged -= OnCollectionChanged;

            Assert.That(capturedArgs, Is.Not.Null);
        }
        public void Add_triggers_both_add_events()
        {
            // Arrange
            var sut = new EventRaisingCollection <Person> (_source);

            sut.BeforeAdd += RecordingCallbackOne;
            sut.AfterAdd  += RecordingCallbackTwo;

            // Act
            sut.Add(new Person());

            sut.BeforeRemove -= RecordingCallbackOne;
            sut.AfterRemove  -= RecordingCallbackTwo;

            // Assert
            Assert.IsTrue(CallbackOneCalled, "Callback one");
            Assert.IsTrue(CallbackTwoCalled, "Callback two");
        }