Add sugar to testing syntax to explicitly state there are no givens/thens

[yreynhout]

new Scenario().
  GivenNone().
  When().
  Then().
  Build();

new Scenario().
  Given().
  When().
  ThenNone().
  Build();

From a twonversation with @jen20 on twitter: https://twitter.com/jen20/status/361957163750539264

[yreynhout]

This would be the new statechart, with the blue states indicating both what's new and transient.

[jen20]

Yup that's pretty much what I was thinking. I have an impl of the the ThenNone if you want a PR, haven't looked at GivenNone none though (have been using ConstructorScenarioFor<T> there.

[yreynhout]

Well, both GivenNone and ThenNone can be achieved "today" in the following ways:

new Scenario().
  When().
  Then().
  Assert();

new Scenario().
  Given().
  When().
  AssertNothingHappened();

but as you mentioned that is only available on the Scenario class and not the Command/Query/Factory/ConstructorScenarioFor<TAggregateRoot> builders. Does your PR include an extra IAggregateXXXThenNoneStateBuilder? If not, I'd rather start from scratch, otherwise somebody could call ThenNone().Then(This).Then(That).Then(SomeMore).Build() which seems counter intuitive and leads down the wrong path.

[yreynhout]

Fixed as of 1b3c35a432b79fa0223dde810db40bc1b4cff18b