/// <summary>
/// Asserts that the specified object raises the <see cref="INotifyPropertyChanged.PropertyChanged"/> event for the specified property.
/// </summary>
/// <typeparam name="TObject">The <see cref="Type">type</see> of <see cref="INotifyPropertyChanged">object</see> to test.</typeparam>
/// <typeparam name="TValue">The <see cref="Type">type</see> of value to assign to the property.</typeparam>
/// <param name="assert">The extended <see cref="Asserter"/>.</param>
/// <param name="subject">The <see cref="INotifyPropertyChanged">object</see> to test.</param>
/// <param name="testProperty">The <see cref="Expression{T}"/> representing the test property.</param>
/// <param name="value">The value to to assign to the tested property.</param>
/// <param name="otherProperties">A sequence of other property <see cref="Expression{T}">expressions</see> representing the additional properties
/// that are expected to change and raise the <see cref="INotifyPropertyChanged.PropertyChanged"/> event as a result of changing the
/// <paramref name="testProperty">tested property</paramref>.</param>
/// <include file="examples.xml" path="Types/Type[@name='INotifyPropertyChangedExtensions']/Member[@name='PropertyChanged`2']/example" />
public static void PropertyChanged <TObject, TValue>(
this Asserter assert,
TObject subject,
Expression <Func <TObject, TValue> > testProperty,
TValue value,
params Expression <Func <TObject, object> >[] otherProperties) where TObject : INotifyPropertyChanged
{
Arg.NotNull(assert, nameof(assert));
assert.AssertParameterIsNotNull(subject, nameof(subject));
assert.AssertParameterIsNotNull(testProperty, nameof(testProperty));
assert.AssertParameterIsNotNull(otherProperties, nameof(otherProperties));
var test = subject.GetTestForProperty(assert, testProperty, out var propertyName);
var unexpected = new HashSet <string>();
var properties = otherProperties.ToDictionary(assert);
properties.Add(propertyName, false);
void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (properties.ContainsKey(e.PropertyName))
{
properties[e.PropertyName] = true;
}
else
{
unexpected.Add(e.PropertyName);
}
}
subject.PropertyChanged += OnPropertyChanged;
try
{
test(subject, value);
}
finally
{
subject.PropertyChanged -= OnPropertyChanged;
}
assert.AllPropertiesWereChanged(properties);
assert.UnexpectedPropertiesWereNotChanged(unexpected);
}