public void canceled_transition_reverts_back_to_original_state()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromSeconds(3), cancellationTokenSource.Token));
factory.StateChanged += (s, e) =>
{
if (e.NewState == State.Stopping)
{
// cancel the stop
cancellationTokenSource.Cancel();
}
};
var startedTask = factory.TransitionTo(State.Started);
var stoppedTask = factory.TransitionTo(State.Stopped, cancellationTokenSource.Token);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
Assert.Equal(State.Started, factory.State);
}
}
public void state_change_is_raised_as_state_changes()
{
var factory = new StateMachineTaskFactory <State>(State.Stopped);
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.FromResult(true));
var stateChanges = new List <StateChangedEventArgs <State> >();
factory.StateChanged += (s, e) => stateChanges.Add(e);
factory.TransitionTo(State.Started).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Stopped).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Started).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Stopped).Wait(TimeSpan.FromSeconds(1));
Assert.Equal(8, stateChanges.Count);
Assert.Equal(State.Stopped, stateChanges[0].OldState);
Assert.Equal(State.Starting, stateChanges[0].NewState);
Assert.Equal(State.Starting, stateChanges[1].OldState);
Assert.Equal(State.Started, stateChanges[1].NewState);
Assert.Equal(State.Started, stateChanges[2].OldState);
Assert.Equal(State.Stopping, stateChanges[2].NewState);
Assert.Equal(State.Stopping, stateChanges[3].OldState);
Assert.Equal(State.Stopped, stateChanges[3].NewState);
Assert.Equal(State.Stopped, stateChanges[4].OldState);
Assert.Equal(State.Starting, stateChanges[4].NewState);
Assert.Equal(State.Starting, stateChanges[5].OldState);
Assert.Equal(State.Started, stateChanges[5].NewState);
Assert.Equal(State.Started, stateChanges[6].OldState);
Assert.Equal(State.Stopping, stateChanges[6].NewState);
Assert.Equal(State.Stopping, stateChanges[7].OldState);
Assert.Equal(State.Stopped, stateChanges[7].NewState);
}
public void transition_to_returns_completed_task_if_already_in_desired_state()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.TransitionTo(State.Started).Wait();
Assert.Equal(TaskStatus.RanToCompletion, factory.TransitionTo(State.Started).Status);
}
public void transition_to_returns_same_task_if_called_multiple_times_whilst_initial_task_is_still_in_progress()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(250)));
var initialTask = factory.TransitionTo(State.Started);
Assert.Equal(initialTask, factory.TransitionTo(State.Started));
Assert.Equal(initialTask, factory.TransitionTo(State.Started));
Assert.Equal(initialTask, factory.TransitionTo(State.Started));
Assert.True(initialTask.Wait(TimeSpan.FromSeconds(3)));
}
public void transition_to_ensures_previous_transition_is_first_completed_before_starting_subsequent_transition()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(10)));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(10)));
var startedAt = DateTime.MinValue;
var stoppedAt = DateTime.MinValue;
var startedTask = factory.TransitionTo(State.Started).ContinueWith(x => startedAt = DateTime.UtcNow, TaskContinuationOptions.ExecuteSynchronously);
var stoppedTask = factory.TransitionTo(State.Stopped).ContinueWith(x => stoppedAt = DateTime.UtcNow, TaskContinuationOptions.ExecuteSynchronously);
Assert.True(Task.WaitAll(new Task[] { startedTask, stoppedTask }, TimeSpan.FromSeconds(3)), "Timed out waiting for tasks to complete.");
Assert.True(stoppedAt > startedAt, "stoppedAt is " + stoppedAt.Millisecond + " and startedAt is " + startedAt.Millisecond + ", difference is " + (stoppedAt - startedAt).ToString());
}
public void transition_to_throws_if_no_transition_registered_for_state()
{
var factory = new StateMachineTaskFactory <State>();
var ex = Assert.Throws <InvalidOperationException>(() => factory.TransitionTo(State.Started));
Assert.Equal("No transition to state 'Started' has been registered.", ex.Message);
}
public void state_gets_the_current_state()
{
var factory = new StateMachineTaskFactory <State>(State.Stopped);
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(100)));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(100)));
var task = factory.TransitionTo(State.Started);
Assert.Equal(State.Starting, factory.State);
task.Wait(TimeSpan.FromSeconds(3));
Assert.Equal(State.Started, factory.State);
task = factory.TransitionTo(State.Stopped);
Assert.Equal(State.Stopping, factory.State);
task.Wait(TimeSpan.FromSeconds(3));
Assert.Equal(State.Stopped, factory.State);
}
public void transition_to_throws_if_task_factory_returns_null()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => null);
var ex = Assert.Throws <InvalidOperationException>(() => factory.TransitionTo(State.Started));
Assert.Equal("Task factory for end state 'Started' returned null.", ex.Message);
}
public void failed_transition_reverts_back_to_original_state()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => { throw new InvalidOperationException("Something went wrong"); });
var startedTask = factory.TransitionTo(State.Started);
var stoppedTask = factory.TransitionTo(State.Stopped);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <InvalidOperationException>(ex.InnerExceptions[0]);
Assert.Equal(State.Started, factory.State);
}
}
public void transition_to_can_be_forbidden()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.FromResult(true));
var startedTask = factory.TransitionTo(State.Started, CancellationToken.None, x => x == State.Undefined);
var stoppedTask = factory.TransitionTo(State.Stopped, CancellationToken.None, x => x != State.Started);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
var ex2 = Assert.IsType <StateTransitionForbiddenException <State> >(ex.InnerExceptions[0]);
Assert.Equal(State.Stopped, ex2.TargetState);
Assert.Equal(State.Started, ex2.State);
Assert.Equal("A transition to state 'Stopped' was forbidden by the validate transition callback.", ex2.Message);
}
}
public void transition_to_can_be_canceled()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(150)));
var startedTask = factory.TransitionTo(State.Started, cancellationTokenSource.Token);
startedTask.ContinueWith(x => cancellationTokenSource.Cancel());
var stoppedTask = factory.TransitionTo(State.Stopped, cancellationTokenSource.Token);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
}
}
public void transition_to_passes_any_state_to_task_creation_function()
{
var factory = new StateMachineTaskFactory <State>();
string receivedState = null;
factory.RegisterTransition(
State.Starting,
State.Started,
(ct, o) =>
{
receivedState = o as string;
return(TaskUtil.FromResult(true));
});
factory.TransitionTo(State.Started, CancellationToken.None, null, "here is the state").Wait();
Assert.Equal("here is the state", receivedState);
}
public void transition_to_can_be_canceled_before_transition_takes_place()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
cancellationTokenSource.Cancel();
var startedTask = factory.TransitionTo(State.Started, cancellationTokenSource.Token);
try
{
startedTask.Wait();
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
}
}