public void Can_except_with()
{
var hashSet = new ObservableHashSet <string> {
"Brendan", "Carmack", "Nate", "Palmer"
};
var countChanging = 0;
var countChanged = 0;
var collectionChanged = 0;
var currentCount = 4;
var countChange = -2;
var removing = new[] { "Carmack", "Palmer" };
hashSet.PropertyChanging += (s, a) => AssertCountChanging(hashSet, s, a, currentCount, ref countChanging);
hashSet.PropertyChanged += (s, a) => AssertCountChanged(hashSet, s, a, ref currentCount, countChange, ref countChanged);
hashSet.CollectionChanged += (s, a) =>
{
Assert.Equal(NotifyCollectionChangedAction.Replace, a.Action);
Assert.Equal(removing, a.OldItems.OfType <string>().OrderBy(i => i));
Assert.Empty(a.NewItems);
collectionChanged++;
};
hashSet.ExceptWith(new[] { "Carmack", "Palmer", "Abrash" });
Assert.Equal(1, countChanging);
Assert.Equal(1, countChanged);
Assert.Equal(1, collectionChanged);
Assert.Equal(new[] { "Brendan", "Nate" }, hashSet.OrderBy(i => i));
hashSet.ExceptWith(new[] { "Abrash", "Carmack", "Palmer" });
Assert.Equal(1, countChanging);
Assert.Equal(1, countChanged);
Assert.Equal(1, collectionChanged);
Assert.Equal(new[] { "Brendan", "Nate" }, hashSet.OrderBy(i => i));
}
public void WhenExceptWithAndOtherDisjoint_ThenDoesNotRaiseCollectionChanged() {
// Arrange
var target = new ObservableHashSet<int>();
target.Add(1);
target.Add(2);
target.Add(3);
target.Add(4);
var other = new int[] { 5, 6 };
bool wasEventRaised = false;
target.CollectionChanged += (s, e) => {
if (e.Action == NotifyCollectionChangedAction.Remove) {
wasEventRaised = true;
}
};
// Act
target.ExceptWith(other);
// Assert
Assert.IsFalse(wasEventRaised);
}
public void WhenExceptWithAndOtherDisjoint_ThenDoesNotRaiseCountPropertyChanged() {
// Arrange
var target = new ObservableHashSet<int>();
target.Add(1);
target.Add(2);
target.Add(3);
target.Add(4);
var other = new int[] { 5, 6 };
bool wasEventRaised = false;
target.PropertyChanged += (s, e) => {
if (e.PropertyName == ObservableHashSet<int>.PropertyNames.Count) {
wasEventRaised = true;
}
};
// Act
target.ExceptWith(other);
// Assert
Assert.IsFalse(wasEventRaised);
}
public void WhenExceptWith_ThenRaisesCollectionChanged() {
// Arrange
var target = new ObservableHashSet<int>();
target.Add(1);
target.Add(2);
target.Add(3);
target.Add(4);
var other = new int[] { 2, 4, 5, 6 };
bool wasEventRaised = false;
target.CollectionChanged += (s, e) => {
if (e.Action == NotifyCollectionChangedAction.Remove &&
e.OldItems.Count == 2 &&
e.OldItems.Contains(2) &&
e.OldItems.Contains(4)) {
wasEventRaised = true;
}
};
// Act
target.ExceptWith(other);
// Assert
Assert.IsTrue(wasEventRaised);
}