All the examples I've read and seen on training videos have simplistic examples. But what I don't see if how I do the "real" code after I get green. Is this the "Refactor" part?
If I have a fairly complex object with a complex method, and I write my test and the bare minimum to make it pass (after it first fails, Red). When do I go back and write the real code? And how much real code do I write before I retest? I'm guessing that last one is more intuition.
Edit: Thanks to all who answered. All your answers helped me immensely. There seems to be different ideas on what I was asking or confused about, and maybe there is, but what I was asking was, say I have an application for building a school.
In my design, I have an architecture I want to start with, User Stories, so on and so forth. From here, I take those User Stories, and I create a test to test the User Story. The User says, We have people enroll for school and pay registration fees. So, I think of a way to make that fail. In doing so I design a test Class for class X (maybe Student), which will fail. I then create the class "Student." Maybe "School" I do not know.
But, in any case, the TD Design is forcing me to think through the story. If I can make a test fail, I know why it fails, but this presupposes I can make it pass. It is about the designing.
I liken this to thinking about Recursion. Recursion is not a hard concept. It may be harder to actually keep track of it in your head, but in reality, the hardest part is knowing, when the recursion "breaks," when to stop (my opinion, of course.) So I have to think about what stops the Recursion first. It is only an imperfect analogy, and it assumes that each recursive iteration is a "pass." Again, just an opinion.
In implementation, The school is harder to see. Numerical and banking ledgers are "easy" in the sense you can use simple arithmetic. I can see a+b and return 0, etc. In the case of a system of people, I have to think harder on how to implement that. I have the concept of the fail, pass, refactor (mostly because of study and this question.)
What I do not know is based upon lack of experience, in my opinion. I do not know how to fail signing up a new student. I do not know how to fail someone typing in a last name and it being saved to a database. I know how to make a+1 for simple math, but with entities like a person, I don't know if I'm only testing to see if I get back a database unique ID or something else when someone enters a name in a database or both or neither.
Or, maybe this shows I am still confused.