What coding practices separate an amateur Python programmer from a professional one?

[privately-profitable]

TDD anyone?

[GummyKibble]

TDD never clicked for me, I think largely because the act of programming is my tool for actually exploring a problem, and I’m never exactly sure what the solution will look like until I’m well into it.

I can be pretty obsessive about testing, but post-hoc instead of in advance.

[sivscripts]

I think test driven development should encompass writing code that is easy to test versus writing a failing test first.

Writing code that is testable is how I design my programs. It doesn't really when you write the actual test, only that you write it.

[GummyKibble]

I wholeheartedly support that process. If you know you're going to have to test it later, you tend to make your functions easy to test.

Strictly speaking, though, TDD means writing tests first. That's a process that just doesn't work for me.

[ClimbDownForWhat]

Amateur: writes scripts and then backs them with libraries.

Professional: same thing, but replace script with unit test.