public void CanExecuteWithParam_CallDelegate()
{
// Arrange
Task Execute() => Task.CompletedTask;
var canExecuteCalled = false;
bool CanExecute()
{
canExecuteCalled = true;
return(true);
}
var errorHandler = new ErrorHandlerTestImplementation((cmd,
exception) =>
{
});
ICommand command = new AsyncCommand(Execute, CanExecute, errorHandler);
// Act
var canExecute = command.CanExecute(null);
// Assert
Assert.IsTrue(canExecute);
Assert.IsTrue(canExecuteCalled);
}
public void RaiseCanExecuteChanged_InvokeEvent()
{
// Arrange
Task Execute() => Task.CompletedTask;
bool CanExecute() => true;
var errorHandler = new ErrorHandlerTestImplementation((cmd,
exception) =>
{
});
object invokedSender = null;
EventArgs invokedArgs = null;
var command = new AsyncCommand(Execute, CanExecute, errorHandler);
command.CanExecuteChanged += (sender,
args) =>
{
invokedSender = sender;
invokedArgs = args;
};
// Act
command.RaiseCanExecuteChanged();
// Assert
Assert.IsNotNull(invokedSender);
Assert.AreSame(command, invokedSender);
Assert.IsNotNull(invokedArgs);
Assert.AreSame(EventArgs.Empty, invokedArgs);
}
public async Task ExecuteAsync_DoNotExecuteWhenCanExecuteReturnsFalse_Async()
{
// Arrange
var executed = false;
Task Execute()
{
executed = true;
return(Task.CompletedTask);
}
bool CanExecute() => false;
var errorHandler = new ErrorHandlerTestImplementation((cmd,
exception) =>
{
});
IAsyncCommand command = new AsyncCommand(Execute, CanExecute, errorHandler);
// Act
await command.ExecuteAsync();
// Assert
Assert.IsFalse(executed);
}
public async Task ExecuteAsync_CorrectExecutionWithCanExecuteChanged_Async()
{
// Arrange
var executed = false;
Task Execute()
{
executed = true;
return(Task.CompletedTask);
}
bool CanExecute() => true;
var errorHandler = new ErrorHandlerTestImplementation((cmd,
exception) =>
{
});
IAsyncCommand command = new AsyncCommand(Execute, CanExecute, errorHandler);
var invokedSenderList = new List <object>();
var invokedArgsList = new List <EventArgs>();
var invokedCanExecuteStateList = new List <bool>();
command.CanExecuteChanged += (sender,
args) =>
{
if (sender != null)
{
invokedSenderList.Add(sender);
}
if (args != null)
{
invokedArgsList.Add(args);
}
invokedCanExecuteStateList.Add(command.CanExecute());
};
// Act
await command.ExecuteAsync();
// Assert
Assert.IsTrue(executed);
Assert.AreEqual(2, invokedSenderList.Count);
Assert.AreSame(command, invokedSenderList[0]);
Assert.AreSame(command, invokedSenderList[1]);
Assert.AreEqual(2, invokedArgsList.Count);
Assert.AreSame(EventArgs.Empty, invokedArgsList[0]);
Assert.AreSame(EventArgs.Empty, invokedArgsList[1]);
Assert.AreEqual(2, invokedCanExecuteStateList.Count);
Assert.IsFalse(invokedCanExecuteStateList[0]); // Cannot execute during first execution, even when the CanExecute delegate returns true.
Assert.IsTrue(invokedCanExecuteStateList[1]); // Can execute after the execution has finished.
}