tests/functional: Adapt reverse_debugging to run w/o Avocado
The goal of this series is to remove Avocado as a dependency for running
the reverse_debugging functional test.
After several rounds of discussions about v1 and v2, and experiments
done by Daniel and Thomas (thanks for all the experiments and comments
so far), I've taken a new approach and moved away from using a runner
for GDB. The changes, I believe, are much simpler now.
This new series uses GDB's machine interface (MI) via the pygdbmi module
(thanks Manos and Peter for the inputs). pygdbmi provides a controller
to start GDB and communicate with it through MI, so there is no longer a
risk of version clashes between libpython in GDB and Python modules in
the pyvenv, as it could, in theory, happen when GDB executes the test
script via -x option.
Also, as Daniel pointed out, the overall test output is pretty bad and
currently does not allow one to easily follow the sequence of GDB
commands used in the test. I took this opportunity to improve the output
and it now prints the sequence in a format that can be copied and pasted
directly into GDB.
The TAP protocol is respected, and Meson correctly displays GDB's test
output in testlog-thorough.txt.
Because the pygdbmi "shim" is so thin, I had to write a trivial GDB
class around it to easily capture and print the payloads returned by its
write() method. The GDB class allows clean, single-line commands to be
used in the tests through method chaining, making them easier to follow,
for example:
pc = gdb.cli("print $pc").get_add()
The test is kept “skipped” for aarch64, ppc64, and x86_64, so it is
necessary to set QEMU_TEST_FLAKY_TESTS=1 in the test environment to
effectively run the test on these archs.
On aarch64, the test is flaky, but there is a fix that I’ve tested while
writing this series [0] that resolves it. On ppc64 and x86_64, the test
always fails: on ppc64, GDB gets a bogus PC, and on x86_64, the last
part of the test (reverse-continue) does not hit the last executed PC
(as it should happen) but instead jumps to the beginning of the code
(first PC in forward order).
Thus, to effectively run the reverse_debugging test on aarch64:
$ export QEMU_TEST_FLAKY_TESTS=1
$ make check-functional
or even, to run only the reverse_debug test after 'make check-functional':
$ ./pyvenv/bin/meson test --verbose --no-rebuild -t 1 --setup thorough --suite func-thorough func-aarch64-reverse_debug
Cheers,
Gustavo
v1:
https://patchew.org/QEMU/20250819143916.4138035-1-gustavo.romero@linaro.org/
v2:
https://patchew.org/QEMU/20250904154640.52687-1-gustavo.romero@linaro.org/
v3:
https://patchew.org/QEMU/20250922054351.14289-1-gustavo.romero@linaro.org/
v4:
- Installed pygdbmi only in check-functional step and using pip,
so not from local wheels (thomas)
- Fixed GDB probe in configure by ensuring that the GDB passed to Meson
supports all that arches in the target list
- Fixed error found by Alex when skipping the test, "name 'test' is not
defined", by using the new decorator suggested by Daniel to skip the
tests if QEMU_TEST_GDB env var is missing (alex, daniel)
- Moved GDB class into its own file under qemu_test, in gdb.py. (alex,
daniel)
- Put subprocess and the drop of the data drainer changes in separate
commits (used previous commits from Daniel for it) (alex, daniel)
- Put back /usr/bin/env python shebang into per arch test files (daniel)
- Added new method reverse_debugging_run() to separate test bootstrap
from GDB test execution, also helping to get a better diff view
(daniel)
- Made diffs better for reviewing by avoiding mixing text changes with
changes in the code related to Avocado's removal (alex, daniel)
Daniel P. Berrangé (2):
tests/functional: replace avocado process with subprocess
tests/functional: drop datadrainer class in reverse debugging
Gustavo Romero (7):
tests/functional: Re-activate the check-venv target
python: Install pygdbmi in meson's venv
tests/functional: Provide GDB to the functional tests
tests/functional: Add GDB class
tests/functional: Add decorator to skip test on missing env vars
tests/functional: Adapt reverse_debugging to run w/o Avocado
tests/functional: Adapt arches to reverse_debugging w/o Avocado
configure | 21 +++
meson_options.txt | 2 +
pythondeps.toml | 1 +
scripts/meson-buildoptions.sh | 2 +
tests/Makefile.include | 2 +-
.../functional/aarch64/test_reverse_debug.py | 9 +-
tests/functional/meson.build | 6 +
tests/functional/ppc64/test_reverse_debug.py | 11 +-
tests/functional/qemu_test/__init__.py | 4 +-
tests/functional/qemu_test/decorators.py | 18 +++
tests/functional/qemu_test/gdb.py | 85 +++++++++++
tests/functional/reverse_debugging.py | 140 ++++++++----------
tests/functional/x86_64/test_reverse_debug.py | 13 +-
13 files changed, 216 insertions(+), 98 deletions(-)
create mode 100644 tests/functional/qemu_test/gdb.py
--
2.34.1