ATF-SH-API(3)

NAME
atf_add_test_case, atf_check, atf_check_equal, atf_config_get, atf_config_has, atf_expect_death, atf_expect_exit, atf_expect_fail, atf_expect_pass, atf_expect_signal, atf_expect_timeout, atf_fail, atf_get, atf_get_srcdir, atf_pass, atf_require_prog, atf_set, atf_skip, atf_test_case - 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_expect_death “reason” “...”
atf_expect_exit “exitcode” “reason” “...”
atf_expect_fail “reason” “...”
atf_expect_pass
atf_expect_signal “signo” “reason” “...”
atf_expect_timeout “reason” “...”
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”
atf_test_case “name” “cleanup”

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 run using the atf-sh(1) interpreter by putting the following on their very first line:

    #! /usr/bin/env atf-sh

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 cleanup
    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 ...
    }

All of these functions are required to return with an exit-status of zero, or ATF will determine that the test is faulty. In particular, this means that none may end with a conditional like:

    atf_sh_function() {
        ... appropriate code here ...
        condition-test && {
    	... more code here ...
        }
    }

as if condition-test fails the return code from atf_sh_function will not be 0. This can be corrected by adding

        return 0

before the end of the function, or by writing it as

    atf_sh_function() {
        ... appropriate code here ...
        if condition-test
        then
    	... more code here ...
        fi
    }

  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 function, which takes a first parameter specifiying the test case's name and instructs the library to set things up to accept it as a valid test case. The second parameter is optional and, if provided, must be ‘cleanup’; providing this parameter allows defining a cleanup routine for the test case. It is important to note that this function 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 <id>_head, <id>_body and <id>_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, or perhaps running simple tests to determine which test cases to add.

  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 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. This message must be a single line (no embedded newline characers.)

  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:

atf_expect_death “reason” “...”
    Expects the test case to exit prematurely regardless of the nature of the exit.

atf_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.

atf_expect_fail “reason”
    Any failure raised in this mode is recorded, but 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.

atf_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’.

atf_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.

atf_expect_timeout “reason” “...”
    Expects the test case to execute for longer than its timeout.

  Helper functions for common checks
atf_check [options] command [args]

This function wraps the execution of the atf-check tool and makes the test case fail if the tool reports failure. You should always use this function instead of the tool in your scripts. For more details on the parameters of this function, refer to atf-check(1).

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 -s exit:0 -o empty -e empty 'true'
    # Check for silent output and failure
    atf_check -s exit:1 -o empty -e empty 'false'
    # Check for known stdout and silent stderr
    echo foo >expout
    atf_check -s exit:0 -o file:expout -e empty 'echo foo'
    # Generate a file for later inspection
    atf_check -s exit:0 -o save:stdout -e empty 'ls'
    grep foo ls || atf_fail "foo file not found in listing"
    # Or just do the match along the way
    atf_check -s exit:0 -o match:"^foo$" -e empty 'ls'

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