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
| atf_check_equal |
“expected_expression”
“actual_expression” |
| 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_signal |
“signo” “reason” “...” |
| atf_expect_timeout |
“reason” “...” |
| atf_require_prog |
“prog_name” |
| atf_set |
“var_name” “value” |
| atf_test_case |
“name” “cleanup” |
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:
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 ...
}
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.
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.
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.
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.
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.
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.
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’, 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.
-
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’, 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.
-
atf_expect_timeout
“reason” “...”
- Expects the test case to execute for longer than its
timeout.
-
atf_check
“[options]” “command”
“[args]”
- 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.
Internally, this function is just a wrapper over the
atf-check(1) tool (whose manual page provides
all details on the calling syntax). You should always use the
atf_check function instead of the
atf-check(1) tool in your scripts; the latter
is not even in the path.
-
atf_check_equal
“expected_expression” “actual_expression”
- 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.
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 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
}
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'
atf-check(1),
atf-sh(1),
atf-test-program(1),
atf-test-case(4)