I am starting work on a personal project which should (hopefully) develop into a startup, the project will need to scale well and I would prefer to invest the time now in TDD.
I am a big Lithium fan, and I am aware that Lithium have their own built in test suite, but I can't find any solid documentation on it and I have never done any real TDD before.
Is there a better way for me to go? Or should I just stick in with Lithium and grind the learning process?
EDIT: Just to clarify. I am talking about PHP Frameworks, not testing frameworks.
If you think, that your project might actually grow into something large, you should write it without the use of framework. The problem with frameworks in general is that they are made with "everything and a kitchen sink" methodology.
You would be much better off, if you build it all from scratch (maybe borrowing some parts you like from Lithium) and use PHPUnit as your testing suite/framework.
Also, i would strongly recommend watching this lecture (and maybe some others from same series), for some general pointers.