what is test cases, and how to decide when to write them?

[Punit Jain]

i have a very basic question, what are test cases, when we write test cases, and for which methods?
i mean can i write test cases for my college project, how do i decide when to write test case?
also i wanted to now what are the types of test cases, like: performance test cases are written to measure performance, what else?

[Jeanne Boyarsky]

Punit,
There are different types of test cases. A test case could be a Word document that you write to describe a scenario. It could be a JUnit class to automatically regression test. IT could be a test written in a QA tool.

You want your test cases to cover all the code. If you are a developer, JUnit test cases are better than Word documents because you can re-run them all at the click of a button.

Types include: functional, performance, regression, etc.

[Punit Jain]

so basically test cases are which only checks that my written code is producing the expected output or not?

[Jeanne Boyarsky]

Or performs in a certain way. Or stores data in a database. Or throws an exception. Or...

[Punit Jain]

okay, Thanks