Hello gokulkmp ,
Unit test cases is purely depend upon the method functionality you need to test.
Like say if you are testing Calculation method (which is user defined function) and functionality of that method is like It will add "A" and "B" and give output as "AB"
so tester would write unit test case
1) call the calculation method and pass "A" as first parameter and "B" as second parameter
2) store output of this method into variable and check that with expected output as 'AB' if it pass then mark test case as pass other wise fail.
There are predefined variable used like "Assert.Pass" / "Assert.Fail"
Please read this
How to write Unit Test cases using VSTS[
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