public void Constructor_WhenCalled_CopiesTransitionTable()
{
var transitionTable =
new List<Transition>
{
new Transition("Locked", "coin", "Unlocked")
};
var sut = new StateMachine(transitionTable);
transitionTable.Add(new Transition("Unlocked", "pass", "Locked"));
Assert.Throws<InvalidOperationException>(
() => sut.GetNewState("Unlocked", "pass"));
}
public void GetNewState_WhenTriggeringEventIsNull_Throws()
{
var sut = new StateMachine(GetTestTransitionTable());
Assert.Throws<ArgumentNullException>(
() => sut.GetNewState("Locked", null));
}
public void GetNewState_WhenTerminalCurrentState_Throws()
{
const string TerminalState = "Terminal";
const string TriggeringEvent = "ev";
var transitionTable =
new List<Transition>
{
new Transition("Whatever", TriggeringEvent, TerminalState)
};
var sut = new StateMachine(transitionTable);
Assert.Throws<InvalidOperationException>(
() => sut.GetNewState(TerminalState, TriggeringEvent));
}
public void GetNewState_WhenValidArguments_ReturnsNewState(
string currentState, string triggeringEvent, string expectedNewState)
{
var sut = new StateMachine(GetTestTransitionTable());
string result = sut.GetNewState(currentState, triggeringEvent);
Assert.Equal(expectedNewState, result);
}
public void GetNewState_WhenInvalidEvent_Throws()
{
var sut = new StateMachine(GetTestTransitionTable());
Assert.Throws<InvalidOperationException>(
() => sut.GetNewState("Locked", "bogus"));
}
public void GetNewState_WhenInvalidCurrentState_Throws()
{
var sut = new StateMachine(GetTestTransitionTable());
var ex = Assert.Throws<InvalidOperationException>(
() => sut.GetNewState("Bogus", "coin"));
Assert.Equal("Invalid state transition: state 'Bogus', event 'coin'.", ex.Message);
}
public void GetNewState_WhenCurrentStateIsNull_Throws()
{
var sut = new StateMachine(GetTestTransitionTable());
Assert.Throws<ArgumentNullException>(
() => sut.GetNewState(null, "coin"));
}