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1. ## Equvalence Class Partioning

Hi all,
hat are Equivalence classes & what is Equivalence Class Partioning?can you define wuth an example?
Rgds
Ankan Mukherjee

2. ## Re: Equvalence Class Partioning

Hi Ankan,
Iam also new to testing ..but i have tried to anwer ur question as per my understanding..let me also learn from other replies..

Equivalence Partioning is dividing the value into equal classes to reduce reduntant testcases.
For example the value to be entered into text box is say 100 - 1500, the we partition the value into 3
-infinity
100-150
+infinity
we shud supply value based on these three partitions.

3. ## Re: Equvalence Class Partioning

Equivalence Partitioning, I think, is eliminating certain test cases because they are, in someway, redundant. For example..., testing both winME and winXP are *sometimes* considered redundant executions.

This was posted earlier here in this forum....Hope this helps

4. ## Re: Equvalence Class Partioning

Prasad is about the closest to the answer. With equivalence Partitioning you are taking a data set or set of test cases and reducing it down to the minimal amount needed to test the range or combinations.

For example, you have an edit field that is numeric only with a range of input of 100 to 1000. You would have two sets of tests for this; one being inputs of numeric only (positive), alphanumeric (mixed & negative condition), and alpha only (negative condition). The second set of tests would be inputs of value for the range of 99 to 1001 (boundary values on outside of range so as to include negative/error condition type inputs).

In the first case do you need to do all three tests, no. You would do the positive path (numeric only) to validate the input procedure. The second test would be the negative path (mixed - alpha numeric) to validate the error trapping. You don't need to do the third one. The third test is an equivalence of the second one. In effect you have reduced the number of tests to perform.

In the second test you would only need to do a few of the input values to validate the field, and not the whole range of values. For the negative condition tests you would do 99 and 1001 to validate the trapping for values out of the range. For the positive tests you would input 100 (right at the border and a valid number in lower range), 1000 (right at the border and a valid number in the upper range), and 500 (valid number in the middle of the range) to validate the input of the field. You don't have to do the other values in the range because you have picked an equivalent sample (combination) of values to validate the field.

This is a pretty basic example, but shows what can be done.

As far as WinME and WinXP being redundant, I don't think so. Both are unique versions of the operating system (ME being the last of the Win9x code base and XP being the latest generation of the NT base, which is different) and need to be tested when compatibility is an issue (especially if your software is either hardware or driver sensitive).

Jim

5. ## Re: Equvalence Class Partioning

Jim:

I slightly disagree with you tests for the second set of conditions. If 99, 100, 1000, 1001 test satisfactorily, 500 is redundant as a subset of the 100 and 1000 tests.

6. ## Re: Equvalence Class Partioning

Originally posted by Darrel Damon:
Jim:

I slightly disagree with your tests for the second set of conditions. If 99, 100, 1000, 1001 test satisfactorily, 500 is redundant as a subset of the 100 and 1000 tests.
<font size="2" face="Verdana, Arial, Helvetica">Darrel,

Agreed, it is possibly a "redundent" value to use and could be dropped. But it satisfies statistically the range of values as it is a median value while the others are boundary type values/conditions. As you know as part of Equivalence class testing (which is statistical sampling in a sense) you should include a "median" value to ensure you "cover" the range.

I guess you could call this the "safe" test to run, because if it doesn't work... then yeah... your in some deep water to start off with.

Point taken.

Jim

7. ## Re: Equvalence Class Partioning

And your point is taken, as well. In reality, I too would probably run the 500 test, even if it had not been documented as a test to run. For my own peace of mind, if nothing else. After all, I don't know a tester worth his or her salt that stops at the scripted tests.

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