Basic unit test and C, how do I get started?

After reading quite some threads here at StackOverflow, I have come to the conclusion that I should adopt to some form of test driven development/unit test (or at least explore the area).

And since we are talking about c code under Linux, I decided to give check a try (I don't know if this is the right choice but if it's no good I can always try something else later on).

But since this concept of unit test and unit test frameworks is totally new to me, I started out to do some unit test on a really small test code (but I was totally lost anyway and it felt like I was missing something).

This is what I have done so far, I created the following file:

main.c, a main that only calls a function called my_pow and prints the result.
my_pow.c, contains the function my_pow.
my_pow.h
my_pow_test.c, I figured that I should place the unit code for the my_pow function here.

(So the "normal program" is the main.c, my_pow.c and my_pow.h.)

This is my_pow.c


#include "my_pow.h"
int my_pow(int a, int b)
{
    return (a*b);
}

Then I figured that in my_pow_test.c I put something like this:


#include <check.h>
#include "my_pow.h"

START_TEST (test_my_pow)
{
    /* unit test code */
}
END_TEST

//do I need some sort off main here that calls test_my_pow?

This is basically the same as in the check manual chapter 3.1, but still not....

Could someone please push me in the right direction?

Thanks Johan

Update: No reason why I tried to use check I just thought I should start somewhere, maybe CUnit is a better choice (I think I would try that as well and then make a educated choice).

Update: Than

Edit Report

1 Answer

I've been using dejagnu for years and love it.

I started using it for embedded development because it supports very well the concept that the machine on which you're running the test program may be different than the machine on which you build the test program. A consequence of this is that testing code on multiple platforms is also well supported. Not sure if that's important. The gcc testsuite uses it. I use it for desktop development as well.

The basic idea with dejagnu is that you

copy the test program to the "target" (which for local testing could be the ~/tmp directory)
start the test program
print stuff to the console (which acts as input to the test program)
parse the output from the test program and match it with what you expect
decide whether that output means pass or fail

Once you've got the test program and the test scripts written, you end up doing something like this:

$ runtest
                === foo Summary ===

# of expected passes            42
foo-test built Thu Jan 15 20:09:19 PST 2009
foo-test version 0.0.0.1
runtest completed at Sun Jan 18 08:29:13 2009

The way I get there for testing a library named foo is:

assume the source and include files for the library are in ~/src/foo
create a directory named ~/src/foo/testsuite
write a test program named foo-test.c that has a main() that

processes command line args
- prints a prompt and sits in a loop processing "commands" where I define a command to test each function in my library. This is sort of like a command shell but specific to the library. For something like my_pow I'd define the command to take 2 args.
write a dejagnu (which is another layer on top of Expect (http://expect.nist.gov/, which is itself a layer on top of Tcl (h

answered 2009-01-18T16:59:18.127

Basic unit test and C, how do I get started?

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