ing your code when you write function or classyou can also write tests for that code testing proves that your code works as it' supposed to in response to all the input types it' designed to receive when you write testsyou can be confident that your code will work correctly as more people begin to use your programs you'll also be able to test new code as you add it to make sure your changes don' break your program' existing behavior every programmer makes mistakesso every programmer must test their code oftencatching problems before users encounter them in this you'll learn to test your code using tools in python' unittest module you'll learn to build test case and check that set of inputs results in the output you want you'll see what passing test looks like and what failing test looks likeand you'll learn how failing test can help you improve your code you'll learn to test functions and classesand you'll start to understand how many tests to write for project