dist/atf-sh/atf-sh-api.3

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.Dd February 29, 2008
.Dt ATF-SH-API 3
.Os
.Sh NAME
.Nm atf_add_test_case ,
.Nm atf_check ,
.Nm atf_check_equal ,
.Nm atf_config_get ,
.Nm atf_config_has ,
.Nm atf_fail ,
.Nm atf_get ,
.Nm atf_get_srcdir ,
.Nm atf_pass ,
.Nm atf_require_prog ,
.Nm atf_set ,
.Nm atf_skip
.Nd POSIX shell API to write ATF-based test programs
.Sh SYNOPSIS
.Fn atf_add_test_case "name"
.Fn atf_check "command"
.Fn atf_check_equal "expr1" "expr2"
.Fn atf_config_get "var_name"
.Fn atf_config_has "var_name"
.Fn atf_fail "reason"
.Fn atf_get "var_name"
.Fn atf_get_srcdir
.Fn atf_pass
.Fn atf_require_prog "prog_name"
.Fn atf_set "var_name" "value"
.Fn atf_skip "reason"
.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 preprocessed by the
.Xr atf-compile 1
tool, which includes some boilerplate code and generates the final
(installable) test program.
.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
tc2_head() {
    ... second test case's header ...
}
tc2_body() {
    ... second test case's body ...
}
tc2_cleanup() {
    ... second test case's cleanup ...
}

.Ns ... 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 8 .
To define test cases, one can use the
.Fn 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
.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
.Fn 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
.Fn <id>_head ,
.Fn <id>_body
and
.Fn <id>_cleanup.
None of these take parameters when executed.
.Ss Program initialization
The test program must define an
.Fn atf_init_test_cases
function, which is in charge of registering the test cases that will be
executed at run time by using the
.Fn 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
.Fn atf_config_has
and
.Fn 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
.Fn atf_get_srcdir
function.
It is interesting to note that this can be used inside
.Fn 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
.Fn 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
.Fn atf_pass ,
.Fn atf_fail
or
.Fn 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
.Fn atf_pass
does not take any parameters.
.Fn atf_fail
and
.Fn 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 Helper functions for common checks
.Fn atf_check cmd expcode expout experr
.Pp
This function takes four parameters: the command to execute, the expected
numerical exit code, the expected behavior of
.Dv stdout
and the expected
behavior of
.Dv stderr .
.Fa expout
can be one of the following:
.Bl -tag -width expoutXX
.It Li expout
What the command writes to the
.Dv stdout
channel must match exactly what is
found in the
.Pa expout
file.
.It Li ignore
The test does not check what the command writes to the
.Dv stdout
channel.
.It Li null
The command must not write anything to the
.Dv stdout
channel.
.It Li stdout
What the command writes to the
.Dv stdout
channel is written to a
.Pa stdout
file, available for further inspection.
.El
.Pp
Similarly,
.Fa experr
can be one of
.Sq Li experr ,
.Sq Li ignore ,
.Sq Li null ,
or
.Sq Li stderr ,
all of which follow the same semantics of their corresponding counterparts
for the
.Fa expout
case.
.Pp
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
.Dv stdout
does not match with the expected contents, a
diff will be printed.
.Pp
.Fn atf_check_equal expr1 expr2
.Pp
This function takes two expressions, evaluates them and, if their
results differ, aborts the test case with an appropriate failure message.
.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 $((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
}
.Ed
.Pp
This other example shows how to include a file with extra helper functions
in the test program:
.Bd -literal -offset indent
.Ns ... 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
.Fn atf_check
function:
.Bd -literal -offset indent
# 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"
.Ed
.Sh SEE ALSO
.Xr atf-compile 1 ,
.Xr atf-test-program 1 ,
.Xr atf 7 ,
.Xr atf-test-case 8