Testing Private Methods/Member Variables - Should you or shouldn't you

re: Testing Private Methods/Member Variables - Should you or shouldn't you

Todd — Mon, 07 Jun 2004 21:55:00 GMT

I am split on whether or not we should be performing tests on private members. When I was first introduced to TDD by a former coworker, his philosophy was "develop for testability". And this would involve exposing members just for the purpose of developing tests against them. Of course, I have come to realize this is a horrible idea. If I were to lean one way, I would say testing only the public interfaces is the way to go. When someone consumes your object, they are only using the public interfaces so writing tests against these members makes sense. However, I can also understand the argument to hit against the private members.

RE: Testing Private Methods/Member Variables - Should you or shouldn't you

nospamplease75@yahoo.com (Haacked) — Mon, 07 Jun 2004 22:29:00 GMT

That's pretty nice. In 99 out of 100 cases, I'd agree that your setting yourself up for a world of hurt if you test this way. It would be better to refactor your code so that the private code gets tested via the appropriate usage of the public interface.

However, this is nice for that 1 case in 100 when you really need to get at the private members to save time in writing tests.

re: Testing Private Methods/Member Variables - Should you or shouldn't you

kevin white — Tue, 08 Jun 2004 03:02:00 GMT

When all you have is a hammer....

The internals of an object certainly should be tested in some way. But unit tested? I don't think so.

Unit testing of private members

jenswinter.com — Tue, 08 Jun 2004 09:15:00 GMT

re: Testing Private Methods/Member Variables - Should you or shouldn't you

Jim Argeropoulos — Tue, 08 Jun 2004 13:19:00 GMT

I like to write all my tests as a part of my class that I am working on. This requires me to have #ifdef all over the place, but I don't mind too much.

That said, I do not test member variables. I only test functions/properties.

I don't like having to make things marked as internal, public just so that I can test it. But I also do test things marked as protected and private. If I have my tests at a granular level, I may have to change my tests more often, but they are more akin to what I would do debugging.

I will experiment with the idea of only testing public interfaces.

re: Unit Testing C# Internal Members

Steven M. Cohn's WebLog — Tue, 08 Jun 2004 16:41:00 GMT

PrivateObject Unit Tester

Steven M. Cohn's WebLog — Wed, 09 Jun 2004 00:32:00 GMT

PrivateObject Unit Tester

Steven M. Cohn's WebLog — Wed, 09 Jun 2004 00:35:00 GMT

re: Testing Private Methods/Member Variables - Should you or shouldn't you

Darren Oakey — Wed, 09 Jun 2004 00:22:00 GMT

There is another option here.

I believe that
a) it is an offense to test below the public interface
b) we should be aiming at 100% test coverage?

ie - every private method should be tested, BUT THROUGH THE PUBLIC INTERFACE. There is _no excuse_ for white box testing - the whole point is that we want to be able to refactor without changing our tests, so you actually decrease stability by allowing white-box testing, because programmers get used to changing unit tests when things go wrong..

However, through the use of smart testing and coverage tools, you should be able to create situations through the public interface that exercise every private field and method. (And if you can't - they shouldn't be there!!!)

TDD - White Box Testing

Todd Kitta's Blog — Wed, 09 Jun 2004 05:18:00 GMT

TDD - White Box Testing

Todd Kitta's Blog — Wed, 09 Jun 2004 05:18:00 GMT

Geek Notes 2004-06-12

Geek Noise — Sun, 13 Jun 2004 06:48:00 GMT

Geek Notes 2004-06-12

Geek Noise — Sun, 13 Jun 2004 06:52:00 GMT

Unit Testing in Whidbey - some pointers for improvement

ISerializable — Mon, 14 Jun 2004 00:15:00 GMT

re: White-box Unit Testing - in whidbey

Barry Gervin's Software Architecture Perspectives — Mon, 14 Jun 2004 06:38:00 GMT

re: Create nUnit test classes in separate projects or in same project as tested classes?

miguel jimenez's coding blog — Tue, 15 Jun 2004 16:31:00 GMT

re: Testing Private Methods/Member Variables - Should you or shouldn't you

James Newkirk — Thu, 17 Jun 2004 01:05:00 GMT

Jay Bazuzi adds some additional information on his blog, check it out.

http://weblogs.asp.net/jaybaz_ms/archive/2004/06/11/153978.aspx

re: Testing Private Methods/Member Variables - Should you or shouldn't you

Clark — Fri, 30 Jul 2004 13:35:00 GMT

While I think this should be rarely used, I think that its important to have the ability to test private methods in certain cases.

Where can I find PrivateObject? Team System is not available yet to the public, right? The best I could find was: http://weblogs.asp.net/stevencohn/archive/2004/06/08/151235.aspx and that isn't quite the same as the above.

Thanks.

Piotr Woloszyn » To test or not to test

Piotr Woloszyn » To test or not to test — Sun, 09 Dec 2007 20:46:30 GMT

PingBack from http://www.woloszyn.org/2007/12/09/to-test-or-not-to-test/