ATF-C++-API(3)

NAME
ATF_ADD_TEST_CASE, ATF_CHECK_ERRNO, ATF_FAIL, ATF_INIT_TEST_CASES, ATF_PASS, ATF_REQUIRE, ATF_REQUIRE_EQ, ATF_REQUIRE_ERRNO, ATF_REQUIRE_MATCH, ATF_REQUIRE_THROW, ATF_REQUIRE_THROW_RE, ATF_SKIP, ATF_TEST_CASE, ATF_TEST_CASE_BODY, ATF_TEST_CASE_CLEANUP, ATF_TEST_CASE_HEAD, ATF_TEST_CASE_WITH_CLEANUP, ATF_TEST_CASE_WITHOUT_HEAD, - C++ API to write ATF-based test programs

SYNOPSIS
#include <atf-c++.hpp>
ATF_ADD_TEST_CASE(tcs, name);
ATF_CHECK_ERRNO(exp_errno, bool_expression);
ATF_FAIL(reason);
ATF_INIT_TEST_CASES(tcs);
ATF_PASS();
ATF_REQUIRE(expression);
ATF_REQUIRE_EQ(expression_1, expression_2);
ATF_REQUIRE_ERRNO(exp_errno, bool_expression);
ATF_REQUIRE_MATCH(regexp, string_expression);
ATF_REQUIRE_THROW(expected_exception, statement);
ATF_REQUIRE_THROW_RE(expected_exception, regexp, statement);
ATF_SKIP(reason);
ATF_TEST_CASE(name);
ATF_TEST_CASE_BODY(name);
ATF_TEST_CASE_CLEANUP(name);
ATF_TEST_CASE_HEAD(name);
ATF_TEST_CASE_WITH_CLEANUP(name);
ATF_TEST_CASE_WITHOUT_HEAD(name);

DESCRIPTION
ATF provides a mostly-macro-based programming interface to implement test programs in C or C++. This interface is backed by a C++ implementation, but this fact is hidden from the developer as much as possible through the use of macros to simplify programming. However, the use of C++ is not hidden everywhere and while you can implement test cases without knowing anything at all about the object model underneath the provided calls, you might need some minimum notions of the language in very specific circumstances.

C++-based test programs always follow this template:

    extern "C" {
    ... C-specific includes go here ...
    }
    ... C++-specific includes go here ...
    #include <atf-c++.hpp>
    ATF_TEST_CASE(tc1);
    ATF_TEST_CASE_HEAD(tc1)
    {
        ... first test case's header ...
    }
    ATF_TEST_CASE_BODY(tc1)
    {
        ... first test case's body ...
    }
    ATF_TEST_CASE_WITH_CLEANUP(tc2);
    ATF_TEST_CASE_HEAD(tc2)
    {
        ... second test case's header ...
    }
    ATF_TEST_CASE_BODY(tc2)
    {
        ... second test case's body ...
    }
    ATF_TEST_CASE_CLEANUP(tc2)
    {
        ... second test case's cleanup ...
    }
    ATF_TEST_CASE(tc3);
    ATF_TEST_CASE_BODY(tc3)
    {
        ... third test case's body ...
    }
    ... additional test cases ...
    ATF_INIT_TEST_CASES(tcs)
    {
        ATF_ADD_TEST_CASE(tcs, tc1);
        ATF_ADD_TEST_CASE(tcs, tc2);
        ATF_ADD_TEST_CASE(tcs, tc3);
        ... add additional test cases ...
    }

  Definition of test cases
Test cases have an identifier and are composed of three different parts: the header, the body and an optional cleanup routine, all of which are described in atf-test-case(4). To define test cases, one can use the ATF_TEST_CASE(), ATF_TEST_CASE_WITH_CLEANUP() or the ATF_TEST_CASE_WITHOUT_HEAD() macros, which take a single parameter specifiying the test case's name. ATF_TEST_CASE(), requires to define a head and a body for the test case, ATF_TEST_CASE_WITH_CLEANUP() requires to define a head, a body and a cleanup for the test case and ATF_TEST_CASE_WITHOUT_HEAD() requires only a body for the test case. It is important to note that these do not set the test case up for execution when the program is run. In order to do so, a later registration is needed through the ATF_ADD_TEST_CASE() macro detailed in Program initialization.

Later on, one must define the three parts of the body by means of three functions. Their headers are given by the ATF_TEST_CASE_HEAD(), ATF_TEST_CASE_BODY() and ATF_TEST_CASE_CLEANUP() macros, all of which take the test case's name. Following each of these, a block of code is expected, surrounded by the opening and closing brackets.

  Program initialization
The library provides a way to easily define the test program's main() function. You should never define one on your own, but rely on the library to do it for you. This is done by using the ATF_INIT_TEST_CASES() macro, which is passed the name of the list that will hold the test cases. This name can be whatever you want as long as it is a valid variable value.

After the macro, you are supposed to provide the body of a function, which should only use the ATF_ADD_TEST_CASE() macro to register the test cases the test program will execute. The first parameter of this macro matches the name you provided in the former call.

  Header definitions
The test case's header can define the meta-data by using the set() method, which takes two parameters: the first one specifies the meta-data variable to be set and the second one specifies its value. Both of them are strings.

  Configuration variables
The test case has read-only access to the current configuration variables by means of the bool has_config_var() and the std::string get_config_var() methods, which can be called in any of the three parts of a test case.

  Access to the source directory
It is possible to get the path to the test case's source directory from any of its three components by querying the ‘srcdir’ configuration variable.

  Requiring programs
Aside from the require.progs meta-data variable available in the header only, one can also check for additional programs in the test case's body by using the require_prog() function, which takes the base name or full path of a single binary. Relative paths are forbidden. If it is not found, the test case will be automatically skipped.

  Test case finalization
The test case finalizes either when the body reaches its end, at which point the test is assumed to have passed, or at any explicit call to ATF_PASS(), ATF_FAIL() or ATF_SKIP(). These three macros terminate the execution of the test case immediately. The cleanup routine will be processed afterwards in a completely automated way, regardless of the test case's termination reason.

ATF_PASS() does not take any parameters. ATF_FAIL() and ATF_SKIP() take a single string that describes why the test case failed or was skipped, respectively. It is very important to provide a clear error message in both cases so that the user can quickly know why the test did not pass.

  Expectations
Everything explained in the previous section changes when the test case expectations are redefined by the programmer.

Each test case has an internal state called ‘expect’ that describes what the test case expectations are at any point in time. The value of this property can change during execution by any of:

expect_death(reason)
    Expects the test case to exit prematurely regardless of the nature of the exit.

expect_exit(exitcode, reason)
    Expects the test case to exit cleanly. If exitcode is not ‘-1’, atf-run(1) will validate that the exit code of the test case matches the one provided in this call. Otherwise, the exact value will be ignored.

expect_fail(reason)
    Any failure (be it fatal or non-fatal) raised in this mode is recorded. However, such failures do not report the test case as failed; instead, the test case finalizes cleanly and is reported as ‘expected failure’; this report includes the provided reason as part of it. If no error is raised while running in this mode, then the test case is reported as ‘failed’.

    This mode is useful to reproduce actual known bugs in tests. Whenever the developer fixes the bug later on, the test case will start reporting a failure, signaling the developer that the test case must be adjusted to the new conditions. In this situation, it is useful, for example, to set reason as the bug number for tracking purposes.

expect_pass()
    This is the normal mode of execution. In this mode, any failure is reported as such to the user and the test case is marked as ‘failed’.

expect_race(reason)
    Any failure or timeout during the execution of the test case will be considered as if a race condition has been triggered and reported as such. If no problems arise, the test will continue execution as usual.

expect_signal(signo, reason)
    Expects the test case to terminate due to the reception of a signal. If signo is not ‘-1’, atf-run(1) will validate that the signal that terminated the test case matches the one provided in this call. Otherwise, the exact value will be ignored.

expect_timeout(reason)
    Expects the test case to execute for longer than its timeout.

  Helper macros for common checks
The library provides several macros that are very handy in multiple situations. These basically check some condition after executing a given statement or processing a given expression and, if the condition is not met, they automatically call ATF_FAIL() with an appropriate error message.

ATF_REQUIRE() takes an expression and raises a failure if it evaluates to false.

ATF_REQUIRE_EQ() takes two expressions and raises a failure if the two do not evaluate to the same exact value.

ATF_REQUIRE_MATCH() takes a regular expression and a string and raises a failure if the regular expression does not match the string.

ATF_REQUIRE_THROW() takes the name of an exception and a statement and raises a failure if the statement does not throw the specified exception. ATF_REQUIRE_THROW_EQ() takes the name of an exception, a regular expresion and a statement and raises a failure if the statement does not throw the specified exception and if the message of the exception does not match the regular expression.

ATF_CHECK_ERRNO() and ATF_REQUIRE_ERRNO() take, first, the error code that the check is expecting to find in the errno variable and, second, a boolean expression that, if evaluates to true, means that a call failed and errno has to be checked against the first value.

EXAMPLES
The following shows a complete test program with a single test case that validates the addition operator:

    #include <atf-c++.hpp>
    ATF_TEST_CASE(addition);
    ATF_TEST_CASE_HEAD(addition)
    {
        set("descr", "Sample tests for the addition operator");
    }
    ATF_TEST_CASE_BODY(addition)
    {
        ATF_REQUIRE_EQ(0 + 0, 0);
        ATF_REQUIRE_EQ(0 + 1, 1);
        ATF_REQUIRE_EQ(1 + 0, 1);
        ATF_REQUIRE_EQ(1 + 1, 2);
        ATF_REQUIRE_EQ(100 + 200, 300);
    }
    ATF_TEST_CASE(open_failure);
    ATF_TEST_CASE_HEAD(open_failure)
    {
        set("descr", "Sample tests for the open function");
    }
    ATF_TEST_CASE_BODY(open_failure)
    {
        ATF_REQUIRE_ERRNO(ENOENT, open("non-existent", O_RDONLY) == -1);
    }
    ATF_TEST_CASE(known_bug);
    ATF_TEST_CASE_HEAD(known_bug)
    {
        set("descr", "Reproduces a known bug");
    }
    ATF_TEST_CASE_BODY(known_bug)
    {
        expect_fail("See bug number foo/bar");
        ATF_REQUIRE_EQ(3, 1 + 1);
        expect_pass();
        ATF_REQUIRE_EQ(3, 1 + 2);
    }
    ATF_INIT_TEST_CASES(tcs)
    {
        ATF_ADD_TEST_CASE(tcs, addition);
        ATF_ADD_TEST_CASE(tcs, open_failure);
        ATF_ADD_TEST_CASE(tcs, known_bug);
    }

SEE ALSO
atf-test-program(1), atf-test-case(4), atf(7)