public void AsyncValueCommand_ChangeCanExecute_Test()
{
// Arrange
var canCommandExecute = false;
var didCanExecuteChangeFire = false;
var command = new AsyncValueCommand(NoParameterTask, commandCanExecute);
command.CanExecuteChanged += handleCanExecuteChanged;
bool commandCanExecute(object parameter) => canCommandExecute;
Assert.False(command.CanExecute(null));
// Act
canCommandExecute = true;
// Assert
Assert.True(command.CanExecute(null));
Assert.False(didCanExecuteChangeFire);
// Act
#pragma warning disable CS0618 // Type or member is obsolete
command.ChangeCanExecute();
#pragma warning restore CS0618 // Type or member is obsolete
// Assert
Assert.True(didCanExecuteChangeFire);
Assert.True(command.CanExecute(null));
void handleCanExecuteChanged(object sender, EventArgs e) => didCanExecuteChangeFire = true;
}
public async Task AsyncValueCommand_ChangeCanExecute_Test()
{
// Arrange
var semaphoreSlim = new SemaphoreSlim(1, 1);
var handleCanExecuteChangedTCS = new TaskCompletionSource <object?>();
var canCommandExecute = false;
var didCanExecuteChangeFire = false;
var command = new AsyncValueCommand(NoParameterTask, commandCanExecute);
command.CanExecuteChanged += handleCanExecuteChanged;
bool commandCanExecute(object?parameter) => canCommandExecute;
Assert.False(command.CanExecute(null));
// Act
canCommandExecute = true;
// Assert
Assert.IsTrue(command.CanExecute(null));
Assert.False(didCanExecuteChangeFire);
// Act
command.ChangeCanExecute();
await handleCanExecuteChangedTCS.Task.ConfigureAwait(false);
// Assert
Assert.IsTrue(didCanExecuteChangeFire);
Assert.IsTrue(command.CanExecute(null));
async void handleCanExecuteChanged(object?sender, EventArgs e)
{
await semaphoreSlim.WaitAsync().ConfigureAwait(false);
try
{
command.CanExecuteChanged -= handleCanExecuteChanged;
didCanExecuteChangeFire = true;
handleCanExecuteChangedTCS.SetResult(null);
}
finally
{
semaphoreSlim.Release();
}
}
}
public async Task AsyncValueCommand_ChangeCanExecute_Test()
{
// Arrange
var handleCanExecuteChangedTCS = new TaskCompletionSource <object>();
var canCommandExecute = false;
var didCanExecuteChangeFire = false;
var command = new AsyncValueCommand(NoParameterTask, commandCanExecute);
command.CanExecuteChanged += handleCanExecuteChanged;
bool commandCanExecute(object parameter) => canCommandExecute;
Assert.False(command.CanExecute(null));
// Act
canCommandExecute = true;
// Assert
Assert.True(command.CanExecute(null));
Assert.False(didCanExecuteChangeFire);
// Act
#pragma warning disable CS0618 // Type or member is obsolete
command.ChangeCanExecute();
await handleCanExecuteChangedTCS.Task;
#pragma warning restore CS0618 // Type or member is obsolete
// Assert
Assert.True(didCanExecuteChangeFire);
Assert.True(command.CanExecute(null));
void handleCanExecuteChanged(object sender, EventArgs e)
{
didCanExecuteChangeFire = true;
handleCanExecuteChangedTCS.SetResult(null);
}
}