Autopkgtest - Defining tests for Debian packages
================================================

This document describes how autopkgtest interprets and executes tests
found in Debian source packages.

Overview
--------

The source package provides a test metadata file
``debian/tests/control``. This is a file containing zero or more
RFC822-style stanzas, along these lines:

::

    Tests: fred, bill, bongo
    Restrictions: needs-root, breaks-testbed

This example defines three tests, called ``fred``, ``bill`` and
``bongo``. The tests will be performed by executing
``debian/tests/fred``, ``debian/tests/bill``, etc. Each test program
should, on success, exit with status 0 and print nothing to stderr; if a
test exits nonzero, or prints to stderr, it is considered to have
failed.

The cwd of each test is guaranteed to be the root of the source package,
which will have been unpacked but not built. *However* note that the
tests must test the *installed* version of the program. Tests may not
modify the source tree (and may not have write access to it).

If the file to be executed has no execute bits set, ``chmod a+x`` is
applied to it (this means that tests can be added in patches without the
need for additional chmod; contrast this with debian/rules).

During execution of the test, the environment variable
``$AUTOPKGTEST_TMP`` will point to a directory for the execution of this
particular test, which starts empty and will be deleted afterwards (so
there is no need for the test to clean up files left there).

If tests want to create artifacts which are useful to attach to test
results, such as additional log files or screenshots, they can put them
into the directory specified by the ``$AUTOPKGTEST_ARTIFACTS``
environment variable. When using the ``--output-dir`` option, they will
be copied into ``outputdir/artifacts/``.

Tests must declare all applicable Restrictions - see below.

The '#' character introduces a comment. Everything from '#' to the end
of line will be entirely ignored.

Control fields
--------------

The fields which may appear in debian/tests/control stanzas are:

Tests: name-of-test [, name-of-another-test ...]
    This field names the tests which are defined by this stanza, and map
    to executables/scripts in the test directory. All of the other
    fields in the same stanza apply to all of the named tests. Either
    this field or ``Test-Command:`` must be present.

    Test names are separated by comma and/or whitespace and should
    contain only characters which are legal in package names. It is
    permitted, but not encouraged, to use upper-case characters as well.

Test-Command: shell command
    If your test only contains a shell command or two, or you want to
    re-use an existing upstream test executable and just need to wrap it
    with some command like ``dbus-launch`` or ``env``, you can use this
    field to specify the shell command directly. It will be run under
    ``bash -e``. This is mutually exclusive with the ``Tests:`` field.

    This is also useful for running the same script under different
    interpreters and/or with different dependencies, such as
    ``Test-Command: python debian/tests/mytest.py`` and
    ``Test-Command: python3 debian/tests/mytest.py``.

Restrictions: restriction-name [, another-restriction-name ...]
    Declares some restrictions or problems with the tests defined in
    this stanza. Depending on the test environment capabilities, user
    requests, and so on, restrictions can cause tests to be skipped or
    can cause the test to be run in a different manner. Tests which
    declare unknown restrictions will be skipped. See below for the
    defined restrictions.

Features: feature-name [, another-feature-name ...]
    Declares some additional capabilities or good properties of the
    tests defined in this stanza. Any unknown features declared will be
    completely ignored. See below for the defined features.

Depends: dpkg dependency field syntax
    Declares that the specified packages must be installed for the test
    to go ahead. This supports all features of dpkg dependencies (see
    https://www.debian.org/doc/debian-policy/ch-relationships.html),
    plus the following extensions:

    ``@`` stands for the package(s) generated by the source package
    containing the tests; each dependency (strictly, or-clause, which
    may contain ``|``\ s but not commas) containing ``@`` is replicated
    once for each such binary package, with the binary package name
    substituted for each ``@`` (but normally ``@`` should occur only
    once and without a version restriction).

    ``@builddeps@`` will be replaced by the package's
    ``Build-Depends:``, ``Build-Depends-Indep:``, and
    ``build-essential``. This is useful if you have many build
    dependencies which are only necessary for running the test suite and
    you don't want to replicate them in the test ``Depends:``. However,
    please use this sparingly, as this can easily lead to missing binary
    package dependencies being overlooked if they get pulled in via
    build dependencies.

    If no Depends field is present, ``Depends: @`` is assumed. Note that
    the source tree's Build-Dependencies are *not* necessarily
    installed, and if you specify any Depends, no binary packages from
    the source are installed unless explicitly requested.

Tests-Directory: path
    Replaces the path segment ``debian/tests`` in the filenames of the
    test programs with ``path``. I. e., the tests are run by executing
    ``built/source/tree/path/testname``. ``path`` must be a relative
    path and is interpreted starting from the root of the built source
    tree.

    This allows tests to live outside the debian/ metadata area, so that
    they can more palatably be shared with non-Debian distributions.

Classes: class-1 [, class-2 ...]
    Most package tests should work in a minimal environment and are
    usually not hardware specific. However, some packages like the
    kernel, X.org, or graphics drivers should be tested on particular
    hardware, and also run on a set of different platforms rather than
    just a single virtual testbeds.

    This field can specify a list of abstract class names such as
    "desktop" or "graphics-driver". Consumers of autopkgtest can then
    map these class names to particular machines/platforms/policies.
    Unknown class names should be ignored.

    This is purely an informational field for autopkgtest itself and
    will be ignored.

Any unknown fields will cause the whole stanza to be skipped.

Defined restrictions
--------------------

rw-build-tree
    The test(s) needs write access to the built source tree (so it may
    need to be copied first). Even with this restriction, the test is
    not allowed to make any change to the built source tree which (i)
    isn't cleaned up by debian/rules clean, (ii) affects the future
    results of any test, or (iii) affects binary packages produced by
    the build tree in the future.

breaks-testbed
    The test, when run, is liable to break the testbed system. This
    includes causing data loss, causing services that the machine is
    running to malfunction, or permanently disabling services; it does
    not include causing services on the machine to temporarily fail.

    When this restriction is present the test will usually be skipped
    unless the testbed's virtualisation arrangements are sufficiently
    powerful, or alternatively if the user explicitly requests.

needs-root
    The test script must be run as root.

build-needed
    The tests need to be run from a built source tree. The test runner
    will build the source tree (honouring the source package's build
    dependencies), before running the tests. However, the tests are
    *not* entitled to assume that the source package's build
    dependencies will be installed when the test is run.

    Please use this considerately, as for large builds it unnecessarily
    builds the entire project when you only need a tiny subset (like the
    tests/ subdirectory). It is often possible to run ``make -C tests``
    instead, or copy the test code to ``$AUTOPKGTEST_TMP`` and build it
    there with some custom commands. This cuts down the load on the
    Continuous Integration servers and also makes tests more robust as
    it prevents accidentally running them against the built source tree
    instead of the installed packages.

allow-stderr
    Output to stderr is not considered a failure. This is useful for
    tests which write e. g. lots of logging to stderr.

isolation-container
    The test wants to start services or open network TCP ports. This
    commonly fails in a simple chroot/schroot, so tests need to be run
    in their own container (e. g. autopkgtest-virt-lxc) or their own
    machine/VM (e. g. autopkgtest-virt-qemu or autopkgtest-virt-null).
    When running the test in a virtualization server which does not
    provide this (like autopkgtest-schroot) it will be skipped.

isolation-machine
    The test wants to interact with the kernel, reboot the machine, or
    other things which fail in a simple schroot and even a container.
    Those tests need to be run in their own machine/VM (e. g.
    autopkgtest-virt-qemu or autopkgtest-virt-null). When running the
    test in a virtualization server which does not provide this it will
    be skipped.

needs-recommends
    Enable installation of recommended packages in apt for the test
    dependencies. This does not affect build dependencies.

Defined features
----------------

There are no currently defined Features.

Source package header
---------------------

To allow test execution environments to discover packages which provide
tests, their source packages should have a ``Testsuite:`` header
containing ``autopkgtest`` (which is currently the only defined value).
Multiple values get comma separated, as usual in control files.

This tag is added automatically by dpkg-source version 1.17.11 or later.
For earlier Debian/Ubuntu releases you need to set it manually in
debian/control by adding

::

    Testsuite: autopkgtest

in the ``Source:`` paragraph.

Automatic test control file for known package types
---------------------------------------------------

There are groups of similarly-structured packages for which the contents
of ``debian/tests/control`` would be mostly identical, such as Perl or
Ruby libraries. If ``debian/tests/control`` is absent, the ``autodep8``
tool can generate an automatic control file. If installed, ``autopkgtest``
will automatically use it; this can be disabled with the
``--no-auto-control`` option.

Those packages do not have to provide ``debian/tests/``, but they should
still include an appropriate source package header
(``Testsuite: autopkgtest-pkg-perl`` or similar) so that they can be
discovered in the archive.

Reboot during a test
--------------------

Some testbeds support rebooting; for those, the testbed will have a
``/tmp/autopkgtest-reboot`` command which tests can call to cause a
reboot.  **Do not** use ``reboot`` and similar commands directly without
at least checking for the presence of that script! They will cause
testbeds like ``null`` or ``schroot`` to reboot the entire host, and
even for ``lxc`` or ``qemu`` it will just cause the test to fail as there
is no state keeping to resume a test at the right position after reboot
without further preparation (see below).

The particular steps for a rebooting tests are:

- The test calls ``/tmp/autopkgtest-reboot my_mark`` with a "mark"
  identifier. ``autopkgtest-reboot`` will cause the test to terminate
  (with ``SIGKILL``).

- autopkgtest backs up the current state of the test source tree and
  any ``$AUTOPKGTEST_ARTIFACTS`` that were created so far, reboots the
  testbed, and restores the test source tree and artifacts.

- The test gets run again, this time with a new environment variable
  ``$AUTOPKGTEST_REBOOT_MARK`` containing the argument to
  ``autopkgtest-reboot``, e. g. ``my_mark``.

- The test needs to check ``$AUTOPKGTEST_REBOOT_MARK`` and jump to the
  appropriate point. A nonexisting variable means "start from the
  beginning".

This example test will reboot the testbed two times in between:

::

    #!/bin/sh -e
    case "$AUTOPKGTEST_REBOOT_MARK" in
      "") echo "test beginning"; /tmp/autopkgtest-reboot mark1 ;;
      mark1) echo "test in mark1"; /tmp/autopkgtest-reboot mark2 ;;
      mark2) echo "test in mark2" ;;
    esac
    echo "test end"

In some cases your test needs to do the reboot by itself, e. g. through
kexec, or a reboot command that is hardcoded in the piece of software
that you want to test. To support those, you need to call
``/tmp/autopkgtest-reboot-prepare my_mark`` at a point as close as
possible to the reboot instead; this will merely save the state but not
issue the actual reboot by itself. Note that all logs and artifacts from
the time between calling ``autopkgtest-reboot-prepare`` and rebooting
will be lost. Other than that, the usage is very similar to above.
Example:

::

    #!/bin/sh
    if [ "$AUTOPKGTEST_REBOOT_MARK" = phase1 ]; then
        echo "continuing test after reboot"
        ls -l /var/post-request-action
        echo "end of test"
    else
        echo "beginning test"
        /tmp/autopkgtest-reboot-prepare phase1
        touch /var/post-request-action
        reboot
    fi

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