In the past I have used debuggers when learning a new language. Helped me to understand what was going on. I'm too impatient to single-step all but the most tr

In the past I have used debuggers when learning a new language. Helped me to understand what was going on. I'm too impatient to single-step all but the most trivial routines. When faced with a new API or algorithm, I write small programs with lots of prints to test/understand the function/object in question. Once that's done I encapsulate as a module and retain some assertions to catch any abuses. I then build systems using the pre-tested modules. At that point I rely on the assertions, logging and exceptions to identify the source of problems. Problems are quickly traced back to the module with bugs which then undergoes further polishing as above.