February 29, 2008 ATF-SH-API 3

### NAME

atf_add_test_case, atf_check, atf_check_equal, atf_config_get, atf_config_has, atf_fail, atf_get, atf_get_srcdir, atf_pass, atf_require_prog, atf_set, atf_skip - POSIX shell API to write ATF-based test programs

### SYNOPSIS

atf_add_test_case(```name`) atf_check(```command`) atf_check_equal(```expr1``, expr2`) atf_config_get(```var_name`) atf_config_has(```var_name`) atf_fail(```reason`) atf_get(```var_name`) atf_get_srcdir(``) atf_pass(``) atf_require_prog(```prog_name`) atf_set(```var_name``, value`) atf_skip(```reason`)

### DESCRIPTION

ATF provides a simple but powerful interface to easily write test programs in the POSIX shell language. These are extremely helpful given that they are trivial to write due to the language simplicity and the great deal of available external tools, so they are often ideal to test other applications at the user level.

Test programs written using this library must be preprocessed by the atf-compile(1) tool, which includes some boilerplate code and generates the final (installable) test program.

Shell-based test programs always follow this template:

  `

      atf_test_case tc1
      tc1_head() {
          ... first test case's header ...
      }
      tc1_body() {
          ... first test case's body ...
      }

      atf_test_case tc2
      tc2_head() {
          ... second test case's header ...
      }
      tc2_body() {
          ... second test case's body ...
      }
      tc2_cleanup() {
          ... second test case's cleanup ...
      }

      ... additional test cases ...

      atf_init_test_cases() {
          atf_add_test_case tc1
          atf_add_test_case 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(``) function, which takes a single parameter specifiying the test case's name and instructs the library to set things up to accept it as a valid test case. It is important to note that it does 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(``) function detailed in Program initialization.

Later on, one must define the three parts of the body by providing two or three functions (remember that the cleanup routine is optional). These functions are named after the test case's identifier, and are _head(``), _body(``) and _cleanup.(``) None of these take parameters when executed.

#### Program initialization

The test program must define an atf_init_test_cases(``) function, which is in charge of registering the test cases that will be executed at run time by using the atf_add_test_case(``) function, which takes the name of a test case as its single parameter. This main function should not do anything else, except maybe sourcing auxiliary source files that define extra variables and functions.

#### Configuration variables

The test case has read-only access to the current configuration variables through the atf_config_has(``) and atf_config_get(``) methods. The former takes a single parameter specifying a variable name and returns a boolean indicating whether the variable is defined or not. The latter can take one or two parameters. If it takes only one, it specifies the variable from which to get the value, and this variable must be defined. If it takes two, the second one specifies a default value to be returned if the variable is not available.

#### Access to the source directory

It is possible to get the path to the test case's source directory from anywhere in the test program by using the atf_get_srcdir(``) function. It is interesting to note that this can be used inside atf_init_test_cases(``) to silently include additional helper files from the source directory.

#### 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 atf_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 functions 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 parameter 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 functions for common checks

atf_check(```cmd``, expcode``, expout``, experr`)

This function takes four parameters: the command to execute, the expected numerical exit code, the expected behavior of ```stdout` and the expected behavior of ```stderr`. ```expout` can be one of the following:

```expout`
  What the command writes to the ```stdout` channel must match exactly what is found in the ```expout` file.

```ignore`
  The test does not check what the command writes to the ```stdout` channel.

```null`
  The command must not write anything to the ```stdout` channel.

```stdout`
  What the command writes to the ```stdout` channel is written to a ```stdout` file, available for further inspection.

Similarly, ```experr` can be one of ````experr`', ````ignore`', ````null`', or ````stderr`', all of which follow the same semantics of their corresponding counterparts for the ```expout` case.

It is important to note that when a failure is detected, this function will print as much information as possible to be able to identify the cause of the failure. For example, if the ```stdout` does not match with the expected contents, a diff will be printed.

atf_check_equal(```expr1``, expr2`)

This function takes two expressions, evaluates them and, if their results differ, aborts the test case with an appropriate failure message.

### EXAMPLES

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

  `

      atf_test_case addition
      addition_head() {
          atf_set "descr" "Sample tests for the addition operator"
      }
      addition_body() {
          atf_check_equal $((0 + 0)) 0
          atf_check_equal $((0 + 1)) 1
          atf_check_equal $((1 + 0)) 0

          atf_check_equal $((1 + 1)) 2

          atf_check_equal $((100 + 200)) 300
      }

      atf_init_test_cases() {
          atf_add_test_case addition
      }

  `

This other example shows how to include a file with extra helper functions in the test program:

  `

      ... definition of test cases ...

      atf_init_test_cases() {
          . $(atf_get_srcdir)/helper_functions.sh

          atf_add_test_case foo1
          atf_add_test_case foo2
      }

  `

This example demonstrates the use of the very useful atf_check(``) function:

  `

      # Check for silent output
      atf_check 'true' 0 null null

      # Check for silent output and failure
      atf_check 'false' 1 null null

      # Check for known stdout and silent stderr
      echo foo >expout
      atf_check 'echo foo' 0 expout null

      # Generate a file for later inspection
      atf_check 'ls' 0 stdout null
      grep foo ls || atf_fail "foo file not found in listing"

  `

### SEE ALSO

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