<P> In test - driven development , each new feature begins with writing a test . Write a test that defines a function or improvements of a function , which should be very succinct . To write a test , the developer must clearly understand the feature 's specification and requirements . The developer can accomplish this through use cases and user stories to cover the requirements and exception conditions , and can write the test in whatever testing framework is appropriate to the software environment . It could be a modified version of an existing test . This is a differentiating feature of test - driven development versus writing unit tests after the code is written : it makes the developer focus on the requirements before writing the code , a subtle but important difference . </P>
<P> In test - driven development , each new feature begins with writing a test . Write a test that defines a function or improvements of a function , which should be very succinct . To write a test , the developer must clearly understand the feature 's specification and requirements . The developer can accomplish this through use cases and user stories to cover the requirements and exception conditions , and can write the test in whatever testing framework is appropriate to the software environment . It could be a modified version of an existing test . This is a differentiating feature of test - driven development versus writing unit tests after the code is written : it makes the developer focus on the requirements before writing the code , a subtle but important difference . </P>
when should the developer test cases be written
when should the developer test cases be written
before writing the code
before writing the code