testing question

[saritha sar]

Hi,
I have the following basic questions in testing please excuse me if they r silly
1.is there any procedure to place test cases in Decisiom table than simply putting input ,expected output in table

2.How do you know when you have enough test cases to adequately test a software module?

3.How can you know if a test case is necessary?

4.How can you predict how long it will take you to test a software system?

Reply is greatly appreciated
Thanks

[Ilja Preuss]

Originally posted by saritha sar:
1.is there any procedure to place test cases in Decisiom table than simply putting input ,expected output in table

Sorry, don't understand this question. Can you elaborate?

2.How do you know when you have enough test cases to adequately test a software module?

3.How can you know if a test case is necessary?

Mostly experience. You observe what bugs get through your net and learn how to write tests to catch them.

One helpfull mathematical technique is to analyse equivalence classes of input values and write at least one test per equivalence class and per boundary value.

4.How can you predict how long it will take you to test a software system?

I can't. In my opinion, testing needs to be done *concurrently* to development, needs to an *integrated* activity. Therefore I can typically only estimate how long a specific feature will take (inclusive testing).

[saritha sar]

Hi,
Thanks alot for your reply.Regarding Question1

1.Can you give detailed explanation on How to place input test cases in Decision Table

Moreover can you clearly explain

One helpfull mathematical technique is to analyse equivalence classes of input values and write at least one test per equivalence class and per boundary value.

What is equivalence class,boundary value?since I am pretty much new testing.
Thanks aot
Waiting for ur reply

[Lasse Koskela]

Originally posted by saritha sar:
What is equivalence class,boundary value?

Let's say you're testing a Calculator that can add numbers.
The input is a pair of integers.

The natural boundary values for all possible input values are
* zero (0)
* the minimum positive value for an integer (1)
* the maximum positive value for an integer (n)
* the minimum negative value for an integer (-n)
* the maximum negative value for an integer (-1)

Now, this group of natural boundaries forms ranges like [2..n-1] and [-2..-n+1]. Within those ranges, it is likely that the Calculator works correctly for value x if it works correctly for value x+1, and so forth. These ranges are (please correct me if I'm wrong here) an example of equivalence classes.

[Ilja Preuss]

http://www.softwaretest.force9.co.uk/cont258.htm