Added BeforeRun option for expensive setup

[jtreuting]

Implemented the BeforeRun that is available in the Ruby version. Followed the current code for handling async. Added a couple simple unit tests at this point to make sure that the method was called if it existed (meaning, not null).

[jtreuting]

I haven't used NSubstitute before so maybe I'm just missing something obvious, but I'm not seeing how it will prevent the need for storing beforeRunRan since the BeforeRun Action doesn't return anything.

I've changed one test to this to use IControlCandidate<T>, what else were you thinking? Thanks.

        var beforeRunRan = false;

        // We introduce side effects for testing. Don't do this in real life please.
        var mock = Substitute.For<IControlCandidate<int>>();
        mock.Control().Returns(42);
        mock.Candidate().Returns(42);
        Action beforeRun = () => { beforeRunRan = true; };

        var result = Scientist.Science<int>("beforeRun", experiment =>
        {
            experiment.BeforeRun(beforeRun);
            experiment.Use(mock.Control);
            experiment.Try(mock.Candidate);
        });

        Assert.Equal(42, result);
        Assert.True(beforeRunRan);

[joncloud]

You should be able to add a new interface method onto IControlCandidate<T> to account for BeforeRun (it can return void, and take no arguments). Then when you use mock to define its behavior, you can use:

mock.Received().BeforeRun()

This will make sure that when you pass experiment.BeforeRun(mock.BeforeRun) the system makes a call into the interface (substituted by NSubstitute). If the system doesn't call into the method, then an exception will be thrown that will turn into a failed test.

[haacked]

Looking good so far. Just need merge master into it or rebase it against master. Sorry for the conflicts!

[jtreuting]

Okay, I merged the upstream master back into mine and resolved the conflicts and made the small changes needed to integrate it with the comparator logic that was added.

[haacked]

Thank you for your contribution!

[haacked]