681eae9bcc
Initial attempt at writing a framework for podman system tests. The idea is to define a useful set of primitives that will make it easy to write actual tests and to interpret results of failing ones. This is a proof-of-concept right now; only a small number of tests, by no means comprehensive. I am requesting review in order to find showstopper problems: reasons why this approach cannot work. Should there be none, we can work toward running these as gating tests for Fedora and RHEL8. Signed-off-by: Ed Santiago <santiago@redhat.com>
Quick overview of podman system tests. The idea is to use BATS, but with a framework for making it easy to add new tests and to debug failures.
Quick Start
Look at 030-run.bats for a simple but packed example. This introduces the basic set of helper functions:
-
setup(implicit) - resets container storage so there's one and only one (standard) image, and no running containers. -
parse_table- you can define tables of inputs and expected results, then read those in awhileloop. This makes it easy to add new tests. Because bash is not a programming language, the caller ofparse_tablesometimes needs to massage the returned values;015-run.batsoffers examples of how to deal with the more typical such issues. -
run_podman- runs command defined in$PODMAN(default: 'podman' but could also be 'podman-remote'), with a timeout. Checks its exit status. -
is- compare actual vs expected output. Emits a useful diagnostic on failure. -
random_string- returns a pseudorandom alphanumeric string
Test files are of the form NNN-name.bats where NNN is a three-digit
number. Please preserve this convention, it simplifies viewing the
directory and understanding test order. Most of the time it's not
important but 00x should be reserved for the times when it matters.
Analyzing test failures
The top priority for this scheme is to make it easy to diagnose
what went wrong. To that end, podman_run always logs all invoked
commands, their output and exit codes. In a normal run you will never
see this, but BATS will display it on failure. The goal here is to
give you everything you need to diagnose without having to rerun tests.
The is comparison function is designed to emit useful diagnostics,
in particular, the actual and expected strings. Please do not use
the horrible BATS standard of [ x = y ]; that's nearly useless
for tracking down failures.
If the above are not enough to help you track down a failure:
Debugging tests
Some functions have dprint statements. To see the output of these,
set PODMAN_TEST_DEBUG="funcname" where funcname is the name of
the function or perhaps just a substring.
Further Details
TBD. For now, look in helpers.bash; each helper function
has (what are intended to be) helpful header comments. For even more
examples, see and/or run helpers.t; that's a regression test
and provides a thorough set of examples of how the helpers work.