April 26, 2008 ATF-C++-API 3

### NAME

ATF_ADD_TEST_CASE, ATF_CHECK, ATF_CHECK_EQUAL, ATF_CHECK_THROW, ATF_FAIL, ATF_INIT_TEST_CASES, ATF_PASS, ATF_SKIP, ATF_TEST_CASE, ATF_TEST_CASE_BODY, ATF_TEST_CASE_CLEANUP, ATF_TEST_CASE_HEAD, ATF_TEST_CASE_WITH_CLEANUP - C++ API to write ATF-based test programs

### SYNOPSIS

ATF_ADD_TEST_CASE(```tcs``, name`) ATF_CHECK(```expression`) ATF_CHECK_EQUAL(```expression_1``, expression_2`) ATF_CHECK_THROW(```statement_1``, expected_exception`) ATF_FAIL(```reason`) ATF_INIT_TEST_CASES(```tcs`) ATF_PASS(``) 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`)

### 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_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 ...
      }

      ... additional test cases ...

      ATF_INIT_TEST_CASES(tcs)
      {
          ATF_ADD_TEST_CASE(tcs, tc1)
          ATF_ADD_TEST_CASE(tcs, tc2)
          ... 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(8). To define test cases, one can use the ATF_TEST_CASE(``) or the ATF_TEST_CASE_WITH_CLEANUP(``) macros, which take a single parameter specifiying the test case's name. The former does not allow the specification of a cleanup routine for the test case while the latter does. 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.

#### 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_CHECK(``) takes an expression and raises a failure if it evaluates to false.

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

ATF_CHECK_THROW(``) takes a statement and the name of an exception and raises a failure if the statement did not throw the specified exception.

### EXAMPLES

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

  `

      #include

      ATF_TEST_CASE(addition);
      ATF_TEST_CASE_HEAD(addition)
      {
          set("descr", "Sample tests for the addition operator");
      }
      ATF_TEST_CASE_BODY(addition)
      {
          ATF_CHECK_EQUAL(0 + 0, 0);
          ATF_CHECK_EQUAL(0 + 1, 1);
          ATF_CHECK_EQUAL(1 + 0, 1);

          ATF_CHECK_EQUAL(1 + 1, 2);

          ATF_CHECK_EQUAL(100 + 200, 300);
      }

      ATF_INIT_TEST_CASES(tcs)
      {
          ATF_ADD_TEST_CASE(tcs, addition);
      }

  `

### SEE ALSO

atf-test-program(1), atf(7), atf-test-case(8)