Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to write unit tests [title] Map your program into units. [step] The key aspect of a good unit test is that it checks just one portion of a program. Whether you are looking to test an existing program, or planning tests for a program that isn't written yet, you'll need to break it down into discrete parts (" units ").

Ending1: This information helps to save work for lab experiments which most programs create. [substeps] Each unit should be considered one unit for speed. Ending2: You'll then write a unit test for each one. [substeps] The definition of a " unit " varies widely depending on the type of program you are developing. Ending3: [substeps] In units 6-12, a unit of a program 18-24 is integrated into a unit's classroom to evaluate its performance. Unit study quizzes are also designed to determine a potential future success in units testing and practices. Ending4: For instance, you will need to review 2.5 units of your current program, which will do most of the work for you. [substeps] You will study process units to the letter, but you will not actually study it.

Answer format: ending1/ending2/ending3/ending4