     [file version.texi not included]

Check
*****

This manual is for Check (version VERSION, UPDATED), a unit testing framework for C.

Copyright © 2001--2014 Arien Malec, Branden Archer, Chris Pickett, Fredrik Hugosson, and Robert Lemmen.

     Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover texts, and no Back-Cover Texts.  A copy of the license is included in the section entitled ``GNU Free Documentation License.''

Please send corrections to this manual to check-devel AT lists.sourceforge.net.  We'd prefer it if you can send a unified diff (diff -u) against the doc/check.texi file that ships with Check, but if that is not possible something is better than nothing.

Introduction
************

Check is a unit testing framework for C.  It was inspired by similar frameworks that currently exist for most programming languages; the most famous example being JUnit (http://www.junit.org) for Java. There is a list of unit test frameworks for multiple languages at http://www.xprogramming.com/software.htm.  Unit testing has a long history as part of formal quality assurance methodologies, but has recently been associated with the lightweight methodology called Extreme Programming.  In that methodology, the characteristic practice involves interspersing unit test writing with coding (``test a little, code a little'').  While the incremental unit test/code approach is indispensable to Extreme Programming, it is also applicable, and perhaps indispensable, outside of that methodology.

The incremental test/code approach provides three main benefits to the developer:

 1. Because the unit tests use the interface to the unit being tested, they allow the developer to think about how the interface should be designed for usage early in the coding process.

 2. They help the developer think early about aberrant cases, and code accordingly.

 3. By providing a documented level of correctness, they allow the developer to refactor (see http://www.refactoring.com) aggressively.

That third reason is the one that turns people into unit testing addicts.  There is nothing so satisfying as doing a wholesale replacement of an implementation, and having the unit tests reassure you at each step of that change that all is well.  It is like the difference between exploring the wilderness with and without a good map and compass: without the proper gear, you are more likely to proceed cautiously and stick to the marked trails; with it, you can take the most direct path to where you want to go.

Look at the Check homepage for the latest information on Check: https://libcheck.github.io/check/.

The Check project page is at: https://github.com/libcheck/check.

Unit Testing in C
*****************

 C unit testing

The approach to unit testing frameworks used for Check originated with Smalltalk, which is a late binding object-oriented language supporting reflection.  Writing a framework for C requires solving some special problems that frameworks for Smalltalk, Java or Python don't have to face.  In all of those language, the worst that a unit test can do is fail miserably, throwing an exception of some sort.  In C, a unit test is just as likely to trash its address space as it is to fail to meet its test requirements, and if the test framework sits in the same address space, goodbye test framework.

To solve this problem, Check uses the fork() system call to create a new address space in which to run each unit test, and then uses message queues to send information on the testing process back to the test framework.  That way, your unit test can do all sorts of nasty things with pointers, and throw a segmentation fault, and the test framework will happily note a unit test error, and chug along.

The Check framework is also designed to play happily with common development environments for C programming.  The author designed Check around Autoconf/Automake (thus the name Check: make check is the idiom used for testing with Autoconf/Automake). Note however that Autoconf/Automake are NOT necessary to use Check; any build system is sufficient. The test failure messages thrown up by Check use the common idiom of filename:linenumber:message used by gcc and family to report problems in source code.  With (X)Emacs, the output of Check allows one to quickly navigate to the location of the unit test that failed; presumably that also works in VI and IDEs.

Other Frameworks for C
======================

The authors know of the following additional unit testing frameworks for C:

AceUnit
     AceUnit (Advanced C and Embedded Unit) bills itself as a comfortable C code unit test framework.  It tries to mimic JUnit 4.x and includes reflection-like capabilities.  AceUnit can be used in resource constraint environments, e.g. embedded software development, and importantly it runs fine in environments where you cannot include a single standard header file and cannot invoke a single standard C function from the ANSI / ISO C libraries.  It also has a Windows port. It does not use forks to trap signals, although the authors have expressed interest in adding such a feature.  See the AceUnit homepage (http://aceunit.sourceforge.net/).

GNU Autounit
     Much along the same lines as Check, including forking to run unit tests in a separate address space (in fact, the original author of Check borrowed the idea from GNU Autounit).  GNU Autounit uses GLib extensively, which means that linking and such need special options, but this may not be a big problem to you, especially if you are already using GTK or GLib.  See the GNU Autounit homepage (http://autounit.tigris.org/).

cUnit
     Also uses GLib, but does not fork to protect the address space of unit tests.  See the archived cUnit homepage (http://web.archive.org/web/*/http://people.codefactory.se/~spotty/cunit/).

CUnit
     Standard C, with plans for a Win32 GUI implementation.  Does not currently fork or otherwise protect the address space of unit tests. In early development.  See the CUnit homepage (http://cunit.sourceforge.net).

CuTest
     A simple framework with just one .c and one .h file that you drop into your source tree.  See the CuTest homepage (http://cutest.sourceforge.net).

CppUnit
     The premier unit testing framework for C++; you can also use it to test C code.  It is stable, actively developed, and has a GUI interface.  The primary reasons not to use CppUnit for C are first that it is quite big, and second you have to write your tests in C++, which means you need a C++ compiler.  If these don't sound like concerns, it is definitely worth considering, along with other C++ unit testing frameworks.  See the CppUnit homepage (http://cppunit.sourceforge.net/cppunit-wiki).

embUnit
     embUnit (Embedded Unit) is another unit test framework for embedded systems.  This one appears to be superseded by AceUnit. Embedded Unit homepage (https://sourceforge.net/projects/embunit/).

MinUnit
     A minimal set of macros and that's it!  The point is to show how easy it is to unit test your code.  See the MinUnit homepage (http://www.jera.com/techinfo/jtns/jtn002.html).

CUnit for Mr. Ando
     A CUnit implementation that is fairly new, and apparently still in early development.  See the CUnit for Mr. Ando homepage (http://park.ruru.ne.jp/ando/work/CUnitForAndo/html/).

This list was last updated in March 2008.  If you know of other C unit test frameworks, please send an email plus description to check-devel AT lists.sourceforge.net and we will add the entry to this list.

It is the authors' considered opinion that forking or otherwise trapping and reporting signals is indispensable for unit testing (but it probably wouldn't be hard to add that to frameworks without that feature).  Try 'em all out: adapt this tutorial to use all of the frameworks above, and use whichever you like.  Contribute, spread the word, and make one a standard.  Languages such as Java and Python are fortunate to have standard unit testing frameworks; it would be desirable that C have one as well.

Tutorial: Basic Unit Testing
****************************

This tutorial will use the JUnit Test Infected (http://junit.sourceforge.net/doc/testinfected/testing.htm) article as a starting point.  We will be creating a library to represent money, libmoney, that allows conversions between different currency types.  The development style will be ``test a little, code a little'', with unit test writing preceding coding. This constantly gives us insights into module usage, and also makes sure we are constantly thinking about how to test our code.

How to Write a Test
===================

Test writing using Check is very simple. The file in which the checks are defined must include check.h as so:

     #include <check.h>

The basic unit test looks as follows:

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

The START_TEST/END_TEST pair are macros that setup basic structures to permit testing.  It is a mistake to leave off the END_TEST marker; doing so produces all sorts of strange errors when the check is compiled.

Setting Up the Money Build Using Autotools
==========================================

Since we are creating a library to handle money, we will first create an interface in money.h, an implementation in money.c, and a place to store our unit tests, check_money.c.  We want to integrate these core files into our build system, and will need some additional structure. To manage everything we'll use Autoconf, Automake, and friends (collectively known as Autotools) for this example.  Note that one could do something similar with ordinary Makefiles, or any other build system. It is in the authors' opinion that it is generally easier to use Autotools than bare Makefiles, and they provide built-in support for running tests.

Note that this is not the place to explain how Autotools works.  If you need help understanding what's going on beyond the explanations here, the best place to start is probably Alexandre Duret-Lutz's excellent Autotools tutorial (http://www.lrde.epita.fr/~adl/autotools.html).

The examples in this section are part of the Check distribution; you don't need to spend time cutting and pasting or (worse) retyping them. Locate the Check documentation on your system and look in the example directory.  The standard directory for GNU/Linux distributions should be /usr/share/doc/check/example.  This directory contains the final version reached the end of the tutorial.  If you want to follow along, create backups of money.h, money.c, and check_money.c, and then delete the originals.

We set up a directory structure as follows:

     .
     |-- Makefile.am
     |-- README
     |-- configure.ac
     |-- src
     |   |-- Makefile.am
     |   |-- main.c
     |   |-- money.c
     |   `-- money.h
     `-- tests
         |-- Makefile.am
         `-- check_money.c

Note that this is the output of tree, a great directory visualization tool.  The top-level Makefile.am is simple; it merely tells Automake how to process sub-directories:

     SUBDIRS = src . tests

Note that tests comes last, because the code should be testing an already compiled library.  configure.ac is standard Autoconf boilerplate, as specified by the Autotools tutorial and as suggested by autoscan.

src/Makefile.am builds libmoney as a Libtool archive, and links it to an application simply called main.  The application's behavior is not important to this tutorial; what's important is that none of the functions we want to unit test appear in main.c; this probably means that the only function in main.c should be main() itself.  In order to test the whole application, unit testing is not appropriate: you should use a system testing tool like Autotest.  If you really want to test main() using Check, rename it to something like _myproject_main() and write a wrapper around it.

The primary build instructions for our unit tests are in tests/Makefile.am:

          [file Makefile.am not included]

TESTS tells Automake which test programs to run for make check.  Similarly, the check_ prefix in check_PROGRAMS actually comes from Automake; it says to build these programs only when make check is run.  (Recall that Automake's check target is the origin of Check's name.)  The check_money test is a program that we will build from tests/check_money.c, linking it against both src/libmoney.la and the installed libcheck.la on our system.  The appropriate compiler and linker flags for using Check are found in @CHECK_CFLAGS@ and @CHECK_LIBS@, values defined by the AM_PATH_CHECK macro.

Now that all this infrastructure is out of the way, we can get on with development.  src/money.h should only contain standard C header boilerplate:

          [file money.1.h not included]

src/money.c should be empty, and tests/check_money.c should only contain an empty main() function:

          [file check_money.1.c not included]

Create the GNU Build System for the project and then build main and libmoney.la as follows:

     $ autoreconf --install
     $ ./configure
     $ make

(autoreconf determines which commands are needed in order for configure to be created or brought up to date. Previously one would use a script called autogen.sh or bootstrap, but that practice is unnecessary now.)

Now build and run the check_money test with make check.  If all goes well, make should report that our tests passed.  No surprise, because there aren't any tests to fail.  If you have problems, make sure to see Supported Build Systems.

This was tested on the isadora distribution of Linux Mint GNU/Linux in November 2012, using Autoconf 2.65, Automake 1.11.1, and Libtool 2.2.6b.  Please report any problems to check-devel AT lists.sourceforge.net.

Setting Up the Money Build Using CMake
======================================

Since we are creating a library to handle money, we will first create an interface in money.h, an implementation in money.c, and a place to store our unit tests, check_money.c.  We want to integrate these core files into our build system, and will need some additional structure. To manage everything we'll use CMake for this example.  Note that one could do something similar with ordinary Makefiles, or any other build system. It is in the authors' opinion that it is generally easier to use CMake than bare Makefiles, and they provide built-in support for running tests.

Note that this is not the place to explain how CMake works.  If you need help understanding what's going on beyond the explanations here, the best place to start is probably the CMake project's homepage (http://www.cmake.org).

The examples in this section are part of the Check distribution; you don't need to spend time cutting and pasting or (worse) retyping them. Locate the Check documentation on your system and look in the example directory, or look in the Check source. If on a GNU/Linux system the standard directory should be /usr/share/doc/check/example. This directory contains the final version reached the end of the tutorial.  If you want to follow along, create backups of money.h, money.c, and check_money.c, and then delete the originals.

We set up a directory structure as follows:

     .
     |-- Makefile.am
     |-- README
     |-- CMakeLists.txt
     |-- cmake
     |   |-- config.h.in
     |   |-- FindCheck.cmake
     |-- src
     |   |-- CMakeLists.txt
     |   |-- main.c
     |   |-- money.c
     |   `-- money.h
     `-- tests
         |-- CMakeLists.txt
         `-- check_money.c

The top-level CMakeLists.txt contains the configuration checks for available libraries and types, and also defines sub-directories to process. The cmake/FindCheck.cmake file contains instructions for locating Check on the system and setting up the build to use it. If the system does not have pkg-config installed, cmake/FindCheck.cmake may not be able to locate Check successfully. In this case, the install directory of Check must be located manually, and the following line added to tests/CMakeLists.txt (assuming Check was installed under C:\\Program Files\\check:

set(CHECK_INSTALL_DIR "C:/Program Files/check")

Note that tests comes last, because the code should be testing an already compiled library.

src/CMakeLists.txt builds libmoney as an archive, and links it to an application simply called main.  The application's behavior is not important to this tutorial; what's important is that none of the functions we want to unit test appear in main.c; this probably means that the only function in main.c should be main() itself.  In order to test the whole application, unit testing is not appropriate: you should use a system testing tool like Autotest.  If you really want to test main() using Check, rename it to something like _myproject_main() and write a wrapper around it.

Now that all this infrastructure is out of the way, we can get on with development.  src/money.h should only contain standard C header boilerplate:

          [file money.1.h not included]

src/money.c should be empty, and tests/check_money.c should only contain an empty main() function:

          [file check_money.1.c not included]

Create the CMake Build System for the project and then build main and libmoney.la as follows for Unix-compatible systems:

     $ cmake .
     $ make

and for MSVC on Windows:

     $ cmake -G "NMake Makefiles" .
     $ nmake

Now build and run the check_money test, with either make test on a Unix-compatible system or nmake test if on Windows using MSVC. If all goes well, the command should report that our tests passed.  No surprise, because there aren't any tests to fail.

This was tested on Windows 7 using CMake 2.8.12.1 and MSVC 16.00.30319.01/ Visual Studios 10 in February 2014. Please report any problems to check-devel AT lists.sourceforge.net.

Test a Little, Code a Little
============================

The Test Infected (http://junit.sourceforge.net/doc/testinfected/testing.htm) article starts out with a Money class, and so will we.  Of course, we can't do classes with C, but we don't really need to.  The Test Infected approach to writing code says that we should write the unit test before we write the code, and in this case, we will be even more dogmatic and doctrinaire than the authors of Test Infected (who clearly don't really get this stuff, only being some of the originators of the Patterns approach to software development and OO design).

Here are the changes to check_money.c for our first unit test:

          [file check_money.1-2.c.diff not included]

A unit test should just chug along and complete.  If it exits early, or is signaled, it will fail with a generic error message.  (Note: it is conceivable that you expect an early exit, or a signal and there is functionality in Check to specifically assert that we should expect a signal or an early exit.)  If we want to get some information about what failed, we need to use some calls that will point out a failure. Two such calls are ck_assert_int_eq (used to determine if two integers are equal) and ck_assert_str_eq (used to determine if two null terminated strings are equal). Both of these functions (actually macros) will signal an error if their arguments are not equal.

An alternative to using ck_assert_int_eq and ck_assert_str_eq is to write the expression under test directly using ck_assert. This takes one Boolean argument which must be True for the check to pass. The second test could be rewritten as follows:

     ck_assert(strcmp (money_currency (m), "USD") == 0);

ck_assert will find and report failures, but will not print any user supplied message in the unit test result. To print a user defined message along with any failures found, use ck_assert_msg. The first argument is a Boolean argument. The remaining arguments support varargs and accept printf-style format strings and arguments.  This is especially useful while debugging. For example, the second test could be rewritten as:

     ck_assert_msg(strcmp (money_currency (m), "USD") == 0,
              "Was expecting a currency of USD, but found %s", money_currency (m));

If the Boolean argument is too complicated to elegantly express within ck_assert(), there are the alternate functions ck_abort() and ck_abort_msg() that unconditionally fail.  The second test inside test_money_create above could be rewritten as follows:

     if (strcmp (money_currency (m), "USD") != 0)
       {
         ck_abort_msg ("Currency not set correctly on creation");
       }

For your convenience ck_assert, which does not accept a user supplied message, substitutes a suitable message for you. (This is also equivalent to passing a NULL message to ck_assert_msg). So you could also write a test as follows:

     ck_assert (money_amount (m) == 5);

This is equivalent to:

     ck_assert_msg (money_amount (m) == 5, NULL);

which will print the file, line number, and the message "Assertion 'money_amount (m) == 5' failed" if money_amount (m) != 5.

When we try to compile and run the test suite now using make check, we get a whole host of compilation errors.  It may seem a bit strange to deliberately write code that won't compile, but notice what we are doing: in creating the unit test, we are also defining requirements for the money interface.  Compilation errors are, in a way, unit test failures of their own, telling us that the implementation does not match the specification.  If all we do is edit the sources so that the unit test compiles, we are actually making progress, guided by the unit tests, so that's what we will now do.

We will patch our header money.h as follows:

          [file money.1-2.h.diff not included]

Our code compiles now, and again passes all of the tests.  However, once we try to use the functions in libmoney in the main() of check_money, we'll run into more problems, as they haven't actually been implemented yet.

Creating a Suite
================

To run unit tests with Check, we must create some test cases, aggregate them into a suite, and run them with a suite runner. That's a bit of overhead, but it is mostly one-off.  Here's a diff for the new version of check_money.c.  Note that we include stdlib.h to get the definitions of EXIT_SUCCESS and EXIT_FAILURE.

          [file check_money.2-3.c.diff not included]

Most of the money_suite() code should be self-explanatory.  We are creating a suite, creating a test case, adding the test case to the suite, and adding the unit test we created above to the test case. Why separate this off into a separate function, rather than inline it in main()?  Because any new tests will get added in money_suite(), but nothing will need to change in main() for the rest of this example, so main will stay relatively clean and simple.

Unit tests are internally defined as static functions.  This means that the code to add unit tests to test cases must be in the same compilation unit as the unit tests themselves.  This provides another reason to put the creation of the test suite in a separate function: you may later want to keep one source file per suite; defining a uniquely named suite creation function allows you later to define a header file giving prototypes for all the suite creation functions, and encapsulate the details of where and how unit tests are defined behind those functions.  See the test program defined for Check itself for an example of this strategy.

The code in main() bears some explanation.  We are creating a suite runner object of type SRunner from the Suite we created in money_suite().  We then run the suite, using the CK_NORMAL flag to specify that we should print a summary of the run, and list any failures that may have occurred.  We capture the number of failures that occurred during the run, and use that to decide how to return.  The check target created by Automake uses the return value to decide whether the tests passed or failed.

Now that the tests are actually being run by check_money, we encounter linker errors again we try out make check.  Try it for yourself and see.  The reason is that the money.c implementation of the money.h interface hasn't been created yet.  Let's go with the fastest solution possible and implement stubs for each of the functions in money.c. Here is the diff:

          [file money.1-3.c.diff not included]

Note that we #include <stdlib.h> to get the definition of NULL.  Now, the code compiles and links when we run make check, but our unit test fails.  Still, this is progress, and we can focus on making the test pass.

SRunner Output
==============

The functions to run tests in an SRunner are defined as follows:

     void srunner_run_all (SRunner * sr, enum print_output print_mode);

     void srunner_run (SRunner *sr, const char *sname, const char *tcname,
                       enum print_output print_mode);

Those functions do two things:

 1. They run all of the unit tests for the selected test cases defined for the selected suites in the SRunner, and collect the results in the SRunner.  The determination of the selected test cases and suites depends on the specific function used.

     srunner_run_all will run all the defined test cases of all defined suites except if the environment variables CK_RUN_CASE or CK_RUN_SUITE are defined.  If defined, those variables shall contain the name of a test suite or a test case, defining in that way the selected suite/test case.

     srunner_run will run the suite/case selected by the sname and tcname parameters.  A value of NULL in some of those parameters means ``any suite/case''.

 2. They print the results according to the print_mode specified.

For SRunners that have already been run, there is also a separate printing function defined as follows:

     void srunner_print (SRunner *sr, enum print_output print_mode);

The enumeration values of print_output defined in Check that parameter print_mode can assume are as follows:

CK_SILENT
     Specifies that no output is to be generated. If you use this flag, you either need to programmatically examine the SRunner object, print separately, or use test logging (see Test Logging.)

CK_MINIMAL
     Only a summary of the test run will be printed (number run, passed, failed, errors).

CK_NORMAL
     Prints the summary of the run, and prints one message per failed test.

CK_VERBOSE
     Prints the summary, and one message per test (passed or failed)

CK_ENV
     Gets the print mode from the environment variable CK_VERBOSITY, which can have the values "silent", "minimal", "normal", "verbose". If the variable is not found or the value is not recognized, the print mode is set to CK_NORMAL.

CK_SUBUNIT
     Prints running progress through the subunit (https://launchpad.net/subunit/) test runner protocol. See 'subunit support' under the Advanced Features section for more information.

With the CK_NORMAL flag specified in our main(), let's rerun make check now. The output from the unit test is as follows:

     Running suite(s): Money
     0%: Checks: 1, Failures: 1, Errors: 0
     check_money.c:9:F:Core:test_money_create:0: Assertion 'money_amount (m)==5' failed:
     money_amount (m)==0, 5==5
     FAIL: check_money
     =====================================================
     1 of 1 test failed
     Please report to check-devel AT lists.sourceforge.net
     =====================================================

Note that the output from make check prior to Automake 1.13 will be the output of the unit test program. Starting with 1.13 Automake will run all unit test programs concurrently and store the output in log files. The output listed above should be present in a log file.

The first number in the summary line tells us that 0% of our tests passed, and the rest of the line tells us that there was one check in total, and of those checks, one failure and zero errors.  The next line tells us exactly where that failure occurred, and what kind of failure it was (P for pass, F for failure, E for error).

After that we have some higher level output generated by Automake: the check_money program failed, and the bug-report address given in configure.ac is printed.

Let's implement the money_amount function, so that it will pass its tests.  We first have to create a Money structure to hold the amount, and then implement the function to return the correct amount:

          [file money.3-4.c.diff not included]

We will now rerun make check and... what's this?  The output is now as follows:

     Running suite(s): Money
     0%: Checks: 1, Failures: 0, Errors: 1
     check_money.c:5:E:Core:test_money_create:0: (after this point)
     Received signal 11 (Segmentation fault)

What does this mean?  Note that we now have an error, rather than a failure.  This means that our unit test either exited early, or was signaled.  Next note that the failure message says ``after this point''; This means that somewhere after the point noted (check_money.c, line 5) there was a problem: signal 11 (a.k.a. segmentation fault).  The last point reached is set on entry to the unit test, and after every call to the ck_assert(), ck_abort(), ck_assert_int_*(), ck_assert_str_*(), or the special function mark_point().  For example, if we wrote some test code as follows:

     stuff_that_works ();
     mark_point ();
     stuff_that_dies ();

then the point returned will be that marked by mark_point().

The reason our test failed so horribly is that we haven't implemented money_create() to create any Money.  We'll go ahead and implement that, the symmetric money_free(), and money_currency() too, in order to make our unit test pass again, here is a diff:

          [file money.4-5.c.diff not included]

Advanced Features
*****************

What you've seen so far is all you need for basic unit testing.  The features described in this section are additions to Check that make it easier for the developer to write, run, and analyze tests.

Convenience Test Functions
==========================

Using the ck_assert function for all tests can lead to lot of repetitive code that is hard to read.  For your convenience Check provides a set of functions (actually macros) for testing often used conditions.

The typical size of an assertion message is less than 80 bytes. However, some of the functions listed below can generate very large messages (up to 4GB allocations were seen in the wild). To prevent this, a limit is placed on the assertion message size. This limit is 4K bytes by default. It can be modified by setting the CK_MAX_MSG_SIZE environment variable, or, if it is not set, by invoking the check_set_max_msg_size() function. If used, this function must be called, once, before the first assertion.

ck_abort
     Unconditionally fails test with default message.

ck_abort_msg
     Unconditionally fails test with user supplied message.

ck_assert
     Fails test if supplied condition evaluates to false.

ck_assert_msg
     Fails test if supplied condition evaluates to false and displays user provided message.

ck_assert_int_eq
ck_assert_int_ne
ck_assert_int_lt
ck_assert_int_le
ck_assert_int_gt
ck_assert_int_ge

     Compares two signed integer values (intmax_t) and displays a predefined message with both the condition and input parameters on failure.  The operator used for comparison is different for each function and is indicated by the last two letters of the function name.  The abbreviations eq, ne, lt, le, gt, and ge correspond to ==, !=, <, <=, >, and >= respectively.

ck_assert_uint_eq
ck_assert_uint_ne
ck_assert_uint_lt
ck_assert_uint_le
ck_assert_uint_gt
ck_assert_uint_ge

     Similar to ck_assert_int_*, but compares two unsigned integer values (uintmax_t) instead.

ck_assert_float_eq
ck_assert_float_ne
ck_assert_float_lt
ck_assert_float_le
ck_assert_float_gt
ck_assert_float_ge

     Compares two floating point numbers (float) and displays a predefined message with both the condition and input parameters on failure. The operator used for comparison is different for each function and is indicated by the last two letters of the function name. The abbreviations eq, ne, lt, le, gt, and ge correspond to ==, !=, <, <=, >, and >= respectively. Beware using those operators for floating point numbers because of precision possible loss on every operation on floating point numbers. For example (1/3)*3==1 would return false, because 1/3==1.333... (or 1.(3) notation in Europe) and cannot be represented by computer logic. As another example 1.1f in fact could be 1.10000002384185791015625 and 2.1f could be 2.099999904632568359375 because of binary representation of floating point numbers. If you have different mathematical operations used on floating point numbers consider using precision comparisons or integer numbers instead. But in some cases those operators could be used. For example if you cyclically increment your floating point number only by positive or only by negative values than you may use <, <=, > and >= operators in tests. If your computations must end up with a certain value than == and != operators may be used.

ck_assert_double_eq
ck_assert_double_ne
ck_assert_double_lt
ck_assert_double_le
ck_assert_double_gt
ck_assert_double_ge

     Similar to ck_assert_float_*, but compares two double precision floating point values (double) instead.

ck_assert_ldouble_eq
ck_assert_ldouble_ne
ck_assert_ldouble_lt
ck_assert_ldouble_le
ck_assert_ldouble_gt
ck_assert_ldouble_ge

     Similar to ck_assert_float_*, but compares two double precision floating point values (long double) instead.

ck_assert_float_eq_tol
ck_assert_float_ne_tol
ck_assert_float_le_tol
ck_assert_float_ge_tol

     Compares two floating point numbers (float) with specified user tolerance set by the third parameter (float) and displays a predefined message with both the condition and input parameters on failure. The abbreviations eq, ne, le, and ge correspond to ==, !=, <=, and >= respectively with acceptable error (tolerance) specified by the last parameter. Beware using those functions for floating comparisons because of (1) errors coming from floating point number representation, (2) rounding errors, (3) floating point errors are platform dependent. Floating point numbers are often internally represented in binary so they cannot be exact power of 10. All these operators have significant error in comparisons so use them only if you know what you're doing. Some assertions could fail on one platform and would be passed on another. For example expression 0.02<=0.01+10^-2 is true by meaning, but some platforms may calculate it as false. IEEE 754 standard specifies the floating point number format representation but it does not promise that the same computation carried out on all hardware will produce the same result.

ck_assert_double_eq_tol
ck_assert_double_ne_tol
ck_assert_double_le_tol
ck_assert_double_ge_tol

     Similar to ck_assert_float_*_tol, but compares two double precision floating point values (double) instead.

ck_assert_ldouble_eq_tol
ck_assert_ldouble_ne_tol
ck_assert_ldouble_le_tol
ck_assert_ldouble_ge_tol

     Similar to ck_assert_float_*_tol, but compares two double precision floating point values (long double) instead.

ck_assert_float_finite

     Checks that a floating point number (float) is finite and displays a predefined message with both the condition and input parameter on failure. Finite means that value cannot be positive infinity, negative infinity or NaN ("Not a Number").

ck_assert_double_finite

     Similar to ck_assert_float_finite, but checks double precision floating point value (double) instead.

ck_assert_ldouble_finite

     Similar to ck_assert_float_finite, but checks double precision floating point value (long double) instead.

ck_assert_float_infinite

     Checks that a floating point number (float) is infinite and displays a predefined message with both the condition and input parameter on failure. Infinite means that value may only be positive infinity or negative infinity.

ck_assert_double_infinite

     Similar to ck_assert_float_infinite, but checks double precision floating point value (double) instead.

ck_assert_ldouble_infinite

     Similar to ck_assert_float_infinite, but checks double precision floating point value (long double) instead.

ck_assert_float_nan

     Checks that a floating point number (float, double or long double abbreviated as ldouble) is NaN ("Not a Number") and displays a predefined message with both the condition and input parameter on failure.

ck_assert_double_nan

     Similar to ck_assert_float_nan, but checks double precision floating point value (double) instead.

ck_assert_ldouble_nan

     Similar to ck_assert_float_nan, but checks double precision floating point value (long double) instead.

ck_assert_float_nonnan

     Checks that a floating point number (float) is not NaN ("Not a Number") and displays a predefined message with both the condition and input parameter on failure.

ck_assert_double_nonnan

     Similar to ck_assert_float_nonnan, but checks double precision floating point value (double) instead.

ck_assert_ldouble_nonnan

     Similar to ck_assert_float_nonnan, but checks double precision floating point value (long double) instead.

ck_assert_str_eq
ck_assert_str_ne
ck_assert_str_lt
ck_assert_str_le
ck_assert_str_gt
ck_assert_str_ge

     Compares two null-terminated char * string values, using the strcmp() function internally, and displays predefined message with condition and input parameter values on failure. The comparison operator is again indicated by last two letters of the function name. ck_assert_str_lt(a, b) will pass if the unsigned numerical value of the character string a is less than that of b. If a NULL pointer is be passed to any comparison macro the check will fail.

ck_assert_pstr_eq
ck_assert_pstr_ne

     Similar to ck_assert_str_* macros, but able to check undefined strings. If a NULL pointer would be passed to a comparison macro it would mean that a string is undefined. If both strings are undefined ck_assert_pstr_eq would pass, but ck_assert_pstr_ne would fail. If only one of strings is undefined ck_assert_pstr_eq macro would fail and ck_assert_pstr_ne would pass.

ck_assert_ptr_eq
ck_assert_ptr_ne

     Compares two pointers and displays predefined message with condition and values of both input parameters on failure.  The operator used for comparison is different for each function and is indicated by the last two letters of the function name.  The abbreviations eq and ne correspond to == and != respectively.

ck_assert_ptr_null
ck_assert_ptr_nonnull

     Compares a pointers against null and displays predefined message with condition and value of the input parameter on failure. ck_assert_ptr_null checks that pointer is equal to NULL and ck_assert_ptr_nonnull checks that pointer is not equal to NULL. ck_assert_ptr_nonnull is highly recommended to use in situations when a function call can return NULL as error indication (like functions that use malloc, calloc, strdup, mmap, etc).

ck_assert_mem_eq
ck_assert_mem_ne
ck_assert_mem_lt
ck_assert_mem_le
ck_assert_mem_gt
ck_assert_mem_ge

     Compares contents of two memory locations of the given length, using the memcmp() function internally, and displays predefined message with condition and input parameter values on failure.  The comparison operator is again indicated by last two letters of the function name. ck_assert_mem_lt(a, b) will pass if the unsigned numerical value of memory location a is less than that of b.

fail
     (Deprecated) Unconditionally fails test with user supplied message.

fail_if
     (Deprecated) Fails test if supplied condition evaluates to true and displays user provided message.

fail_unless
     (Deprecated) Fails test if supplied condition evaluates to false and displays user provided message.

Running Multiple Cases
======================

What happens if we pass -1 as the amount in money_create()?  What should happen?  Let's write a unit test. Since we are now testing limits, we should also test what happens when we create Money where amount == 0.  Let's put these in a separate test case called ``Limits'' so that money_suite is changed like so:

          [file check_money.3-6.c.diff not included]

Now we can rerun our suite, and fix the problem(s). Note that errors in the ``Core'' test case will be reported as ``Core'', and errors in the ``Limits'' test case will be reported as ``Limits'', giving you additional information about where things broke.

          [file money.5-6.c.diff not included]

No Fork Mode
============

Check normally forks to create a separate address space.  This allows a signal or early exit to be caught and reported, rather than taking down the entire test program, and is normally very useful.  However, when you are trying to debug why the segmentation fault or other program error occurred, forking makes it difficult to use debugging tools.  To define fork mode for an SRunner object, you can do one of the following:

 1. Define the CK_FORK environment variable to equal ``no''.

 2. Explicitly define the fork status through the use of the following function:

     void srunner_set_fork_status (SRunner * sr, enum fork_status fstat);

The enum fork_status allows the fstat parameter to assume the following values: CK_FORK and CK_NOFORK.  An explicit call to srunner_set_fork_status() overrides the CK_FORK environment variable.

Test Fixtures
=============

We may want multiple tests that all use the same Money.  In such cases, rather than setting up and tearing down objects for each unit test, it may be convenient to add some setup that is constant across all the tests in a test case.  Each such setup/teardown pair is called a test fixture in test-driven development jargon.

A fixture is created by defining a setup and/or a teardown function, and associating it with a test case.  There are two kinds of test fixtures in Check: checked and unchecked fixtures. These are defined as follows:

Checked fixtures
     are run inside the address space created by the fork to create the unit test.  Before each unit test in a test case, the setup() function is run, if defined. After each unit test, the teardown() function is run, if defined.  Since they run inside the forked address space, if checked fixtures signal or otherwise fail, they will be caught and reported by the SRunner.  A checked teardown() fixture will not run if the unit test fails.

Unchecked fixtures
     are run in the same address space as the test program. Therefore they may not signal or exit, but may use the fail functions. The unchecked setup(), if defined, is run before the test case is started. The unchecked teardown(), if defined, is run after the test case is done. An unchecked teardown() fixture will run even if a unit test fails.

An important  difference is that the checked fixtures are run once per unit test and the unchecked fixtures are run once per test case. So for a test case that contains check_one() and check_two() unit tests, checked_setup()/checked_teardown() checked fixtures, and unchecked_setup()/unchecked_teardown() unchecked fixtures, the control flow would be:

     unchecked_setup();
     fork();
     checked_setup();
     check_one();
     checked_teardown();
     wait();
     fork();
     checked_setup();
     check_two();
     checked_teardown();
     wait();
     unchecked_teardown();

Test Fixture Examples
---------------------

We create a test fixture in Check as follows:

 1. Define global variables, and functions to setup and teardown the globals.  The functions both take void and return void. In our example, we'll make five_dollars be a global created and freed by setup() and teardown() respectively.

 2. Add the setup() and teardown() functions to the test case with tcase_add_checked_fixture().  In our example, this belongs in the suite setup function money_suite.

 3. Rewrite tests to use the globals.  We'll rewrite our first to use five_dollars.

Note that the functions used for setup and teardown do not need to be named setup() and teardown(), but they must take void and return void.  We'll update check_money.c with the following patch:

          [file check_money.6-7.c.diff not included]

Checked vs Unchecked Fixtures
-----------------------------

Checked fixtures run once for each unit test in a test case, and so they should not be used for expensive setup.  However, if a checked fixture fails and CK_FORK mode is being used, it will not bring down the entire framework.

On the other hand, unchecked fixtures run once for an entire test case, as opposed to once per unit test, and so can be used for expensive setup.  However, since they may take down the entire test program, they should only be used if they are known to be safe.

Additionally, the isolation of objects created by unchecked fixtures is not guaranteed by CK_NOFORK mode.  Normally, in CK_FORK mode, unit tests may abuse the objects created in an unchecked fixture with impunity, without affecting other unit tests in the same test case, because the fork creates a separate address space. However, in CK_NOFORK mode, all tests live in the same address space, and side effects in one test will affect the unchecked fixture for the other tests.

A checked fixture will generally not be affected by unit test side effects, since the setup() is run before each unit test.  There is an exception for side effects to the total environment in which the test program lives: for example, if the setup() function initializes a file that a unit test then changes, the combination of the teardown() function and setup() function must be able to restore the environment for the next unit test.

If the setup() function in a fixture fails, in either checked or unchecked fixtures, the unit tests for the test case, and the teardown() function for the fixture will not be run.  A fixture error will be created and reported to the SRunner.

Multiple Suites in one SRunner
==============================

In a large program, it will be convenient to create multiple suites, each testing a module of the program.  While one can create several test programs, each running one Suite, it may be convenient to create one main test program, and use it to run multiple suites.  The Check test suite provides an example of how to do this. The main testing program is called check_check, and has a header file that declares suite creation functions for all the module tests:

     Suite *make_sub_suite (void);
     Suite *make_sub2_suite (void);
     Suite *make_master_suite (void);
     Suite *make_list_suite (void);
     Suite *make_msg_suite (void);
     Suite *make_log_suite (void);
     Suite *make_limit_suite (void);
     Suite *make_fork_suite (void);
     Suite *make_fixture_suite (void);
     Suite *make_pack_suite (void);

The function srunner_add_suite() is used to add additional suites to an SRunner.  Here is the code that sets up and runs the SRunner in the main() function in check_check_main.c:

     SRunner *sr;
     sr = srunner_create (make_master_suite ());
     srunner_add_suite (sr, make_list_suite ());
     srunner_add_suite (sr, make_msg_suite ());
     srunner_add_suite (sr, make_log_suite ());
     srunner_add_suite (sr, make_limit_suite ());
     srunner_add_suite (sr, make_fork_suite ());
     srunner_add_suite (sr, make_fixture_suite ());
     srunner_add_suite (sr, make_pack_suite ());

Selective Running of Tests
==========================

After adding a couple of suites and some test cases in each, it is sometimes practical to be able to run only one suite, or one specific test case, without recompiling the test code.  Check provides two ways to accomplish this, either by specifying a suite or test case by name or by assigning tags to test cases and specifying one or more tags to run.

Selecting Tests by Suite or Test Case
-------------------------------------

There are two environment variables available that offer this ability, CK_RUN_SUITE and CK_RUN_CASE. Just set the value to the name of the suite and/or test case you want to run. These environment variables can also be a good integration tool for running specific tests from within another tool, e.g. an IDE.

Selecting Tests Based on Arbitrary Tags
---------------------------------------

It can be useful to dynamically include or exclude groups of tests to be run based on criteria other than the suite or test case name. For example, one or more tags can be assigned to test cases. The tags could indicate if a test runs for a long time, so such tests could be excluded in order to run quicker tests for a sanity check. Alternately, tags may be used to indicate which functional areas test cover. Tests can then be run that include all test cases for a given set of functional areas.

In Check, a tag is a string of characters without white space. One or more tags can be assigned to a test case by using the tcase_set_tags function. This function accepts a string, and multiple tags can be specified by delimiting them with spaces. For example:

         Suite *s;

         TCase *red, *blue, *purple, *yellow, *black;

         s = suite_create("Check Tag Filtering");

         red = tcase_create("Red");
         tcase_set_tags(red, "Red");
         suite_add_tcase (s, red);
         tcase_add_test(red, red_test1);

         blue = tcase_create("Blue");
         tcase_set_tags(blue, "Blue");
         suite_add_tcase (s, blue);
         tcase_add_test(blue, blue_test1);

         purple = tcase_create("Purple");
         tcase_set_tags(purple, "Red Blue");
         suite_add_tcase (s, purple);
         tcase_add_test(purple, purple_test1);

Once test cases are tagged they may be selectively run in one of two ways:

a) Using Environment Variables

There are two environment variables available for selecting test cases based on tags: CK_INCLUDE_TAGS and CK_EXCLUDE_TAGS. These can be set to a space separated list of tag names. If CK_INCLUDE_TAGS is set then test cases which include at least one tag in common with CK_INCLUDE_TAGS will be run. If CK_EXCLUDE_TAGS is set then test cases with one tag in common with CK_EXCLUDE_TAGS will not be run. In cases where both CK_INCLUDE_TAGS and CK_EXCLUDE_TAGS match a tag for a test case the test will be excluded.

Both CK_INCLUDE_TAGS and CK_EXCLUDE_TAGS can be specified in conjunction with CK_RUN_SUITE or even CK_RUN_CASE in which case they will have the effect of further narrowing the selection.

b) Programmatically

The srunner_run_tagged function allows one to specify which tags to run or exclude from a suite runner. This can be used to programmatically control which test cases may run.

Testing Signal Handling and Exit Values
=======================================

To enable testing of signal handling, there is a function tcase_add_test_raise_signal() which is used instead of tcase_add_test().  This function takes an additional signal argument, specifying a signal that the test expects to receive.  If no signal is received this is logged as a failure.  If a different signal is received this is logged as an error.

The signal handling functionality only works in CK_FORK mode.

To enable testing of expected exits, there is a function tcase_add_exit_test() which is used instead of tcase_add_test(). This function takes an additional expected exit value argument, specifying a value that the test is expected to exit with.  If the test exits with any other value this is logged as a failure.  If the test exits early this is logged as an error.

The exit handling functionality only works in CK_FORK mode.

Looping Tests
=============

Looping tests are tests that are called with a new context for each loop iteration.  This makes them ideal for table based tests.  If loops are used inside ordinary tests to test multiple values, only the first error will be shown before the test exits.  However, looping tests allow for all errors to be shown at once, which can help out with debugging.

Adding a normal test with tcase_add_loop_test() instead of tcase_add_test() will make the test function the body of a for loop, with the addition of a fork before each call.  The loop variable _i is available for use inside the test function; for example, it could serve as an index into a table.  For failures, the iteration which caused the failure is available in error messages and logs.

Start and end values for the loop are supplied when adding the test. The values are used as in a normal for loop.  Below is some pseudo-code to show the concept:

     for (_i = tfun->loop_start; _i < tfun->loop_end; _i++)
     {
       fork();      /* New context */
       tfun->f(_i);  /* Call test function */
       wait();      /* Wait for child to terminate */
     }

An example of looping test usage follows:

     static const int primes[5] = {2,3,5,7,11};

     START_TEST (check_is_prime)
     {
       ck_assert (is_prime (primes[_i]));
     }
     END_TEST

     ...

     tcase_add_loop_test (tcase, check_is_prime, 0, 5);

Looping tests work in CK_NOFORK mode as well, but without the forking.  This means that only the first error will be shown.

Test Timeouts
=============

To be certain that a test won't hang indefinitely, all tests are run with a timeout, the default being 4 seconds.  If the test is not finished within that time, it is killed and logged as an error.

The timeout for a specific test case, which may contain multiple unit tests, can be changed with the tcase_set_timeout() function. The default timeout used for all test cases can be changed with the environment variable CK_DEFAULT_TIMEOUT, but this will not override an explicitly set timeout.  Another way to change the timeout length is to use the CK_TIMEOUT_MULTIPLIER environment variable, which multiplies all timeouts, including those set with tcase_set_timeout(), with the supplied integer value. All timeout arguments are in seconds and a timeout of 0 seconds turns off the timeout functionality. On systems that support it, the timeout can be specified using a nanosecond precision. Otherwise, second precision is used.

Test timeouts are only available in CK_FORK mode.

Determining Test Coverage
=========================

The term code coverage refers to the extent that the statements of a program are executed during a run.  Thus, test coverage refers to code coverage when executing unit tests.  This information can help you to do two things:

  * Write better tests that more fully exercise your code, thereby improving confidence in it.

  * Detect dead code that could be factored away.

Check itself does not provide any means to determine this test coverage; rather, this is the job of the compiler and its related tools.  In the case of gcc this information is easy to obtain, and other compilers should provide similar facilities.

Using gcc, first enable test coverage profiling when building your source by specifying the -fprofile-arcs and -ftest-coverage switches:

     $ gcc -g -Wall -fprofile-arcs -ftest-coverage -o foo foo.c foo_check.c

You will see that an additional .gcno file is created for each .c input file.  After running your tests the normal way, a .gcda file is created for each .gcno file.  These contain the coverage data in a raw format.  To combine this information and a source file into a more readable format you can use the gcov utility:

     $ gcov foo.c

This will produce the file foo.c.gcov which looks like this:

          -:   41:     * object */
         18:   42:    if (ht->table[p] != NULL) {
          -:   43:        /* replaces the current entry */
      #####:   44:        ht->count--;
      #####:   45:        ht->size -= ht->table[p]->size +
      #####:   46:          sizeof(struct hashtable_entry);

As you can see this is an annotated source file with three columns: usage information, line numbers, and the original source.  The usage information in the first column can either be '-', which means that this line does not contain code that could be executed; '#####', which means this line was never executed although it does contain code---these are the lines that are probably most interesting for you; or a number, which indicates how often that line was executed.

This is of course only a very brief overview, but it should illustrate how determining test coverage generally works, and how it can help you.  For more information or help with other compilers, please refer to the relevant manuals.

Finding Memory Leaks
====================

It is possible to determine if any code under test leaks memory during a test. Check itself does not have an API for memory leak detection, however Valgrind can be used against a unit testing program to search for potential leaks.

Before discussing memory leak detection, first a "memory leak" should be better defined. There are two primary definitions of a memory leak:

 1. Memory that is allocated but not freed before a program terminates. However, it was possible for the program to free the memory if it had wanted to. Valgrind refers to these as "still reachable" leaks.

 2. Memory that is allocated, and any reference to the memory is lost. The program could not have freed the memory. Valgrind refers to these as "definitely lost" leaks.

Valgrind uses the second definition by default when defining a memory leak. These leaks are the ones which are likely to cause a program issues due to heap depletion.

If one wanted to run Valgrind against a unit testing program to determine if leaks are present, the following invocation of Valgrind will work:

     valgrind --leak-check=full ${UNIT_TEST_PROGRAM}
     ...
     ==3979== LEAK SUMMARY:
     ==3979==    definitely lost: 0 bytes in 0 blocks
     ==3979==    indirectly lost: 0 bytes in 0 blocks
     ==3979==      possibly lost: 0 bytes in 0 blocks
     ==3979==    still reachable: 548 bytes in 24 blocks
     ==3979==         suppressed: 0 bytes in 0 blocks

In that example, there were no "definitely lost" memory leaks found. However, why would there be such a large number of "still reachable" memory leaks? It turns out this is a consequence of using fork() to run a unit test in its own process memory space, which Check does by default on platforms with fork() available.

Consider the example where a unit test program creates one suite with one test. The flow of the program will look like the following:

     Main process:       Unit test process:
     create suite
     srunner_run_all()
        fork unit test     unit test process created
        wait for test      start test
        ...                end test
        ...                exit(0)
        test complete
     report result
     free suite
     exit(0)

The unit testing process has a copy of all memory that the main process allocated. In this example, that would include the suite allocated in main. When the unit testing process calls exit(0), the suite allocated in main() is reachable but not freed. As the unit test has no reason to do anything besides die when its test is finished, and it has no reasonable way to free everything before it dies, Valgrind reports that some memory is still reachable but not freed.

If the "still reachable" memory leaks are a concern, and one required that the unit test program report that there were no memory leaks regardless of the type, then the unit test program needs to run without fork. To accomplish this, either define the CK_FORK=no environment variable, or use the srunner_set_fork_status() function to set the fork mode as CK_NOFORK for all suite runners.

Running the same unit test program by disabling fork() results in the following:

     CK_FORK=no valgrind --leak-check=full ${UNIT_TEST_PROGRAM}
     ...
     ==4924== HEAP SUMMARY:
     ==4924==     in use at exit: 0 bytes in 0 blocks
     ==4924==   total heap usage: 482 allocs, 482 frees, 122,351 bytes allocated
     ==4924==
     ==4924== All heap blocks were freed -- no leaks are possible

Test Logging
============

Check supports an operation to log the results of a test run.  To use test logging, call the srunner_set_log() function with the name of the log file you wish to create:

     SRunner *sr;
     sr = srunner_create (make_s1_suite ());
     srunner_add_suite (sr, make_s2_suite ());
     srunner_set_log (sr, "test.log");
     srunner_run_all (sr, CK_NORMAL);

In this example, Check will write the results of the run to test.log.  The print_mode argument to srunner_run_all() is ignored during test logging; the log will contain a result entry, organized by suite, for every test run.  Here is an example of test log output:

     Running suite S1
     ex_log_output.c:8:P:Core:test_pass: Test passed
     ex_log_output.c:14:F:Core:test_fail: Failure
     ex_log_output.c:18:E:Core:test_exit: (after this point) Early exit
     with return value 1
     Running suite S2
     ex_log_output.c:26:P:Core:test_pass2: Test passed
     Results for all suites run:
     50%: Checks: 4, Failures: 1, Errors: 1

Another way to enable test logging is to use the CK_LOG_FILE_NAME environment variable. When set tests will be logged to the specified file name. If log file is specified with both CK_LOG_FILE_NAME and srunner_set_log(), the name provided to srunner_set_log() will be used.

If the log name is set to "-" either via srunner_set_log() or CK_LOG_FILE_NAME, the log data will be printed to stdout instead of to a file.

XML Logging
-----------

The log can also be written in XML.  The following functions define the interface for XML logs:

     void srunner_set_xml (SRunner *sr, const char *fname);
     int srunner_has_xml (SRunner *sr);
     const char *srunner_xml_fname (SRunner *sr);

XML output is enabled by a call to srunner_set_xml() before the tests are run. Here is an example of an XML log:

     <?xml version="1.0"?>
     <?xml-stylesheet type="text/xsl" href="http://check.sourceforge.net/xml/check_unittest.xslt"?>
     <testsuites xmlns="http://check.sourceforge.net/ns">
       <datetime>2012-10-19 09:56:06</datetime>
       <suite>
         <title>S1</title>
         <test result="success">
           <path>.</path>
           <fn>ex_xml_output.c:10</fn>
           <id>test_pass</id>
           <iteration>0</iteration>
           <duration>0.000013</duration>
           <description>Core</description>
           <message>Passed</message>
         </test>
         <test result="failure">
           <path>.</path>
           <fn>ex_xml_output.c:16</fn>
           <id>test_fail</id>
           <iteration>0</iteration>
           <duration>-1.000000</duration>
           <description>Core</description>
           <message>Failure</message>
         </test>
         <test result="error">
           <path>.</path>
           <fn>ex_xml_output.c:20</fn>
           <id>test_exit</id>
           <iteration>0</iteration>
           <duration>-1.000000</duration>
           <description>Core</description>
           <message>Early exit with return value 1</message>
         </test>
       </suite>
       <suite>
         <title>S2</title>
         <test result="success">
           <path>.</path>
           <fn>ex_xml_output.c:28</fn>
           <id>test_pass2</id>
           <iteration>0</iteration>
           <duration>0.000011</duration>
           <description>Core</description>
           <message>Passed</message>
         </test>
         <test result="failure">
           <path>.</path>
           <fn>ex_xml_output.c:34</fn>
           <id>test_loop</id>
           <iteration>0</iteration>
           <duration>-1.000000</duration>
           <description>Core</description>
           <message>Iteration 0 failed</message>
         </test>
         <test result="success">
           <path>.</path>
           <fn>ex_xml_output.c:34</fn>
           <id>test_loop</id>
           <iteration>1</iteration>
           <duration>0.000010</duration>
           <description>Core</description>
           <message>Passed</message>
         </test>
         <test result="failure">
           <path>.</path>
           <fn>ex_xml_output.c:34</fn>
           <id>test_loop</id>
           <iteration>2</iteration>
           <duration>-1.000000</duration>
           <description>Core</description>
           <message>Iteration 2 failed</message>
         </test>
       </suite>
       <suite>
         <title>XML escape &quot; &apos; &lt; &gt; &amp; tests</title>
         <test result="failure">
           <path>.</path>
           <fn>ex_xml_output.c:40</fn>
           <id>test_xml_esc_fail_msg</id>
           <iteration>0</iteration>
           <duration>-1.000000</duration>
           <description>description &quot; &apos; &lt; &gt; &amp;</description>
           <message>fail &quot; &apos; &lt; &gt; &amp; message</message>
         </test>
       </suite>
       <duration>0.001610</duration>
     </testsuites>

XML logging can be enabled by an environment variable as well. If CK_XML_LOG_FILE_NAME environment variable is set, the XML test log will be written to specified file name. If XML log file is specified with both CK_XML_LOG_FILE_NAME and srunner_set_xml(), the name provided to srunner_set_xml() will be used.

If the log name is set to "-" either via srunner_set_xml() or CK_XML_LOG_FILE_NAME, the log data will be printed to stdout instead of to a file.

If both plain text and XML log files are specified, by any of above methods, then check will log to both files. In other words logging in plain text and XML format simultaneously is supported.

TAP Logging
-----------

The log can also be written in Test Anything Protocol (TAP) format. Refer to the TAP Specification (http://podwiki.hexten.net/TAP/TAP.html) for information on valid TAP output and parsers of TAP. The following functions define the interface for TAP logs:

     void srunner_set_tap (SRunner *sr, const char *fname);
     int srunner_has_tap (SRunner *sr);
     const char *srunner_tap_fname (SRunner *sr);

TAP output is enabled by a call to srunner_set_tap() before the tests are run. Here is an example of an TAP log:

     ok 1 - mytests.c:test_suite_name:my_test_1: Passed
     ok 2 - mytests.c:test_suite_name:my_test_2: Passed
     not ok 3 - mytests.c:test_suite_name:my_test_3: Foo happened
     ok 4 - mytests.c:test_suite_name:my_test_1: Passed
     1..4

TAP logging can be enabled by an environment variable as well. If CK_TAP_LOG_FILE_NAME environment variable is set, the TAP test log will be written to specified file name. If TAP log file is specified with both CK_TAP_LOG_FILE_NAME and srunner_set_tap(), the name provided to srunner_set_tap() will be used.

If the log name is set to "-" either via srunner_set_tap() or CK_TAP_LOG_FILE_NAME, the log data will be printed to stdout instead of to a file.

If both plain text and TAP log files are specified, by any of above methods, then check will log to both files. In other words logging in plain text and TAP format simultaneously is supported.

Subunit Support
===============

Check supports running test suites with subunit output. This can be useful to combine test results from multiple languages, or to perform programmatic analysis on the results of multiple check test suites or otherwise handle test results in a programmatic manner. Using subunit with check is very straight forward. There are two steps: 1) In your check test suite driver pass 'CK_SUBUNIT' as the output mode for your srunner.

     SRunner *sr;
     sr = srunner_create (make_s1_suite ());
     srunner_add_suite (sr, make_s2_suite ());
     srunner_run_all (sr, CK_SUBUNIT);

2) Setup your main language test runner to run your check based test executable. For instance using python:

     import subunit

     class ShellTests(subunit.ExecTestCase):
         """Run some tests from the C codebase."""

         def test_group_one(self):
             """./foo/check_driver"""

         def test_group_two(self):
             """./foo/other_driver"""

In this example, running the test suite ShellTests in python (using any test runner - unittest.py, tribunal, trial, nose or others) will run ./foo/check_driver and ./foo/other_driver and report on their result.

Subunit is hosted on launchpad - the subunit (https://launchpad.net/subunit/) project there contains bug tracker, future plans, and source code control details.

Supported Build Systems
***********************

Check officially supports two build systems: Autotools and CMake. Primarily it is recommended to use Autotools where possible, as CMake is only officially supported for Windows. Information on using Check in either build system follows.

Autotools
=========

It is recommended to use pkg-config where possible to locate and use Check in an Autotools project. This can be accomplished by including the following in the project's configure.ac file:

   PKG_CHECK_MODULES([CHECK], [check >= MINIMUM-VERSION])

where MINIMUM-VERSION is the lowest version which is sufficient for the project. For example, to guarantee that at least version 0.9.6 is available, use the following:

   PKG_CHECK_MODULES([CHECK], [check >= 0.9.6])

An example of a configure.ac script for a project is included in the doc/example directory in Check's source. This macro should provide everything necessary to integrate Check into an Autotools project.

If one does not wish to use pkg-config Check also provides its own macro, AM_PATH_CHECK(), which may be used. This macro is deprecated, but is still included with Check for backwards compatibility.

The AM_PATH_CHECK() macro is defined in the file check.m4 which is installed by Check.  It has some optional parameters that you might find useful in your configure.ac:
AM_PATH_CHECK([MINIMUM-VERSION,
               [ACTION-IF-FOUND[,ACTION-IF-NOT-FOUND]]])

AM_PATH_CHECK does several things:

 1. It ensures check.h is available

 2. It ensures a compatible version of Check is installed

 3. It sets CHECK_CFLAGS and CHECK_LIBS for use by Automake.

If you include AM_PATH_CHECK() in configure.ac and subsequently see warnings when attempting to create configure, it probably means one of the following things:

 1. You forgot to call aclocal.  autoreconf will do this for you.

 2. aclocal can't find  check.m4.  Here are some possible solutions:

      a. Call aclocal with -I set to the location of check.m4.  This means you have to call both aclocal and autoreconf.

      b. Add the location of check.m4 to the dirlist used by aclocal and then call autoreconf.  This means you need permission to modify the dirlist.

      c. Set ACLOCAL_AMFLAGS in your top-level Makefile.am to include -I DIR with DIR being the location of check.m4.  Then call autoreconf.

CMake
=====

Those unable to use Autotools in their project may use CMake instead. Officially CMake is supported only for Windows.

Documentation for using CMake is forthcoming. In the meantime, look at the example CMake project in Check's doc/examples directory.

If you are using CMake version 3 or above, importing Check into your project is easier than in earlier versions. If you have installed Check as a CMake library, you should have the following files:

${INSTALL_PREFIX}/lib/cmake/check/check-config.cmake and
${INSTALL_PREFIX}/lib/cmake/check/check-config-version.cmake and

If you haven't installed Check into a system directory, you have to tell your CMake build how to find it:

cmake -Dcheck_ROOT=${INSTALL_PREFIX}

Then use Check in your @file{CMakeLists.txt} like this:

@verbatim
find_package(check <check_version if wanted> REQUIRED CONFIG)

add_executable(myproj.test myproj.test.c)
target_link_libraries(myproj.test Check::check)
add_test(NAME MyProj COMMAND myproj.test)

Conclusion and References
*************************

The tutorial and description of advanced features has provided an introduction to all of the functionality available in Check. Hopefully, this is enough to get you started writing unit tests with Check.  All the rest is simply application of what has been learned so far with repeated application of the ``test a little, code a little'' strategy.

For further reference, see Kent Beck, ``Test-Driven Development: By Example'', 1st ed., Addison-Wesley, 2003.  ISBN 0-321-14653-0.

If you know of other authoritative references to unit testing and test-driven development, please send us a patch to this manual.

Environment Variable Reference
******************************

This is a reference to environment variables that Check recognized and their use.

CK_RUN_CASE: Name of a test case, runs only that test. See section Selective Running of Tests.

CK_RUN_SUITE: Name of a test suite, runs only that suite. See section Selective Running of Tests.

CK_INCLUDE_TAGS: String of space separated tags, runs only test cases associated with at least one of the tags, See section Selecting Tests Based on Arbitrary Tags.

CK_EXCLUDE_TAGS: String of space separated tags, runs only test cases not associated with any of the tags, See section Selecting Tests Based on Arbitrary Tags.

CK_VERBOSITY: How much output to emit, accepts: ``silent'', ``minimal'', ``normal'', ``subunit'', or ``verbose''.  See section SRunner Output.

CK_FORK: Set to ``no'' to disable using fork() to run unit tests in their own process. This is useful for debugging segmentation faults.  See section No Fork Mode.

CK_DEFAULT_TIMEOUT: Override Check's default unit test timeout, a floating value in seconds. ``0'' means no timeout.  See section Test Timeouts.

CK_TIMEOUT_MULTIPLIER: A multiplier used against the default unit test timeout. An integer, defaults to ``1''.  See section Test Timeouts.

CK_LOG_FILE_NAME: Filename to write logs to.  See section Test Logging.

CK_XML_LOG_FILE_NAME: Filename to write XML log to. See section XML Logging.

CK_TAP_LOG_FILE_NAME: Filename to write TAP (Test Anything Protocol) output to.  See section TAP Logging.

CK_MAX_MSG_SIZE: Maximal assertion message size.

Copying This Manual
*******************

     [file fdl.texi not included]