atf/atf-sh/atf-sh.3

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.Dd January 27, 2021
.Dt ATF-SH 3
.Os
.Sh NAME
.Nm atf_add_test_case ,
.Nm atf_check ,
.Nm atf_check_equal ,
.Nm atf_check_not_equal ,
.Nm atf_config_get ,
.Nm atf_config_has ,
.Nm atf_expect_death ,
.Nm atf_expect_exit ,
.Nm atf_expect_fail ,
.Nm atf_expect_pass ,
.Nm atf_expect_signal ,
.Nm atf_expect_timeout ,
.Nm atf_fail ,
.Nm atf_get ,
.Nm atf_get_srcdir ,
.Nm atf_init_test_cases ,
.Nm atf_pass ,
.Nm atf_require_prog ,
.Nm atf_set ,
.Nm atf_skip ,
.Nm atf_test_case
.Nd POSIX shell API to write ATF-based test programs
.Sh SYNOPSIS
.Nm atf_add_test_case
.Qq name
.Nm atf_check
.Qq command
.Nm atf_check_equal
.Qq expected_expression
.Qq actual_expression
.Nm atf_check_not_equal
.Qq expected_expression
.Qq actual_expression
.Nm atf_config_get
.Qq var_name
.Nm atf_config_has
.Qq var_name
.Nm atf_expect_death
.Qq reason
.Qq ...
.Nm atf_expect_exit
.Qq exitcode
.Qq reason
.Qq ...
.Nm atf_expect_fail
.Qq reason
.Qq ...
.Nm atf_expect_pass
.Qq
.Nm atf_expect_signal
.Qq signo
.Qq reason
.Qq ...
.Nm atf_expect_timeout
.Qq reason
.Qq ...
.Nm atf_fail
.Qq reason
.Nm atf_get
.Qq var_name
.Nm atf_get_srcdir
.Nm atf_init_test_cases
.Qq name
.Nm atf_pass
.Nm atf_require_prog
.Qq prog_name
.Nm atf_set
.Qq var_name
.Qq value
.Nm atf_skip
.Qq reason
.Nm atf_test_case
.Qq name
.Qq cleanup
.Sh 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.
.Pp
Test programs written using this library must be run using the
.Xr atf-sh 1
interpreter by putting the following on their very first line:
.Bd -literal -offset indent
#! /usr/bin/env atf-sh
.Ed
.Pp
Shell-based test programs always follow this template:
.Bd -literal -offset indent
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 ...
}
.Ed
.Ss 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
.Xr atf-test-case 4 .
To define test cases, one can use the
.Nm atf_test_case
function, which takes a first parameter specifying 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
.Sq cleanup ;
providing this parameter allows defining a cleanup routine for the test
case.
It is important to note that this function
.Em 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
.Nm atf_add_test_case
function detailed in
.Sx Program initialization .
.Pp
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
.Nm \*(Ltid\*(Gt_head ,
.Nm \*(Ltid\*(Gt_body
and
.Nm \*(Ltid\*(Gt_cleanup .
None of these take parameters when executed.
.Ss Program initialization
The test program must define an
.Nm atf_init_test_cases
function, which is in charge of registering the test cases that will be
executed at run time by using the
.Nm 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.
.Ss Configuration variables
The test case has read-only access to the current configuration variables
through the
.Nm atf_config_has
and
.Nm 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.
.Ss 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
.Nm atf_get_srcdir
function.
It is interesting to note that this can be used inside
.Nm atf_init_test_cases
to silently include additional helper files from the source directory.
.Ss Requiring programs
Aside from the
.Va 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
.Nm 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.
.Ss Test case finalization
The test case finalizes either when the body reaches its end, at which
point the test is assumed to have
.Em passed ,
or at any explicit call to
.Nm atf_pass ,
.Nm atf_fail
or
.Nm 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.
.Pp
.Nm atf_pass
does not take any parameters.
.Nm atf_fail
and
.Nm 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.
.Ss Expectations
Everything explained in the previous section changes when the test case
expectations are redefined by the programmer.
.Pp
Each test case has an internal state called
.Sq 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:
.Bl -tag -width indent
.It Nm atf_expect_death Qo reason Qc Qo ... Qc
Expects the test case to exit prematurely regardless of the nature of the
exit.
.It Nm atf_expect_exit Qo exitcode Qc Qo reason Qc Qo ... Qc
Expects the test case to exit cleanly.
If
.Va exitcode
is not
.Sq -1 ,
the runtime engine will validate that the exit code of the test case
matches the one provided in this call.
Otherwise, the exact value will be ignored.
.It Nm atf_expect_fail Qo reason Qc
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
.Sq expected failure ;
this report includes the provided
.Fa reason
as part of it.
If no error is raised while running in this mode, then the test case is
reported as
.Sq failed .
.Pp
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
.Fa reason
as the bug number for tracking purposes.
.It Nm 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
.Sq failed .
.It Nm atf_expect_signal Qo signo Qc Qo reason Qc Qo ... Qc
Expects the test case to terminate due to the reception of a signal.
If
.Va signo
is not
.Sq -1 ,
the runtime engine will validate that the signal that terminated the test
case matches the one provided in this call.
Otherwise, the exact value will be ignored.
.It Nm atf_expect_timeout Qo reason Qc Qo ... Qc
Expects the test case to execute for longer than its timeout.
.El
.Ss Helper functions for common checks
.Bl -tag -width indent
.It Nm atf_check Qo [options] Qc Qo command Qc Qo [args] Qc
Executes a command, performs checks on its exit code and its output, and
fails the test case if any of the checks is not successful.
This function is particularly useful in integration tests that verify the
correct functioning of a binary.
.Pp
Internally, this function is just a wrapper over the
.Xr atf-check 1
tool (whose manual page provides all details on the calling syntax).
You should always use the
.Nm atf_check
function instead of the
.Xr atf-check 1
tool in your scripts; the latter is not even in the path.
.It Nm atf_check_equal Qo expected_expression Qc Qo actual_expression Qc
This function takes two expressions, evaluates them and, if their
results differ, aborts the test case with an appropriate failure message.
The common style is to put the expected value in the first parameter and the
actual value in the second parameter.
.It Nm atf_check_not_equal Qo expected_expression Qc Qo actual_expression Qc
This function takes two expressions, evaluates them and, if their
results are equal, aborts the test case with an appropriate failure message.
The common style is to put the expected value in the first parameter and the
actual value in the second parameter.
.El
.Sh EXAMPLES
The following shows a complete test program with a single test case that
validates the addition operator:
.Bd -literal -offset indent
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 1 $((0 + 1))
    atf_check_equal 1 $((1 + 0))

    atf_check_equal 2 $((1 + 1))

    atf_check_equal 300 $((100 + 200))
}

atf_init_test_cases() {
    atf_add_test_case addition
}
.Ed
.Pp
This other example shows how to include a file with extra helper functions
in the test program:
.Bd -literal -offset indent
\&... definition of test cases ...

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

    atf_add_test_case foo1
    atf_add_test_case foo2
}
.Ed
.Pp
This example demonstrates the use of the very useful
.Nm atf_check
function:
.Bd -literal -offset indent
# 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
.Ed
.Sh SEE ALSO
.Xr atf-check 1 ,
.Xr atf-sh 1 ,
.Xr atf-test-program 1 ,
.Xr atf-test-case 4