Re: [Qemu-devel] [PATCH v4 1/3] Bootstrap Python venv for tests

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Caio,

On 15/10/2018 20:41, Caio Carrara wrote:
> On 13-10-2018 00:37, Eduardo Habkost wrote:
>> On Fri, Oct 12, 2018 at 11:30:39PM +0200, Philippe Mathieu-Daudé wrote:
>>> Hi Cleber,
>>>
>>> On 12/10/2018 18:53, Cleber Rosa wrote:
>>>> A number of QEMU tests are written in Python, and may benefit
>>>> from an untainted Python venv.
>>>>
>>>> By using make rules, tests that depend on specific Python libs
>>>> can set that rule as a requirement, along with rules that require
>>>> the presence or installation of specific libraries.
>>>>
>>>> The tests/venv-requirements.txt is supposed to contain the
>>>> Python requirements that should be added to the venv created
>>>> by check-venv.
>>>
>>> Maybe you (or Eduardo...) what you wrote in the cover:
>>>
>>>  There's one current caveat: it requires Python 3, as it's based on the
>>>  venv module.
>>>
>>> To explain:
>>>
>>> $ make check-acceptance
>>> /usr/bin/python2: No module named venv
>>> make: *** [/home/phil/source/qemu/tests/Makefile.include:1033:] Error 1
>>
>> Oops, this doesn't look very friendly.
>>
>> But note that this would become a non-issue if we start requiring
>> Python 3 for building QEMU.
>>
>>
>>>
>>>>
>>>> Signed-off-by: Cleber Rosa <crosa@redhat.com>
>>>> ---
>>>>  tests/Makefile.include      | 20 ++++++++++++++++++++
>>>>  tests/venv-requirements.txt |  3 +++
>>>>  2 files changed, 23 insertions(+)
>>>>  create mode 100644 tests/venv-requirements.txt
>>>>
>>>> diff --git a/tests/Makefile.include b/tests/Makefile.include
>>>> index 5eadfd52f9..b66180efa1 100644
>>>> --- a/tests/Makefile.include
>>>> +++ b/tests/Makefile.include
>>>> @@ -12,6 +12,7 @@ check-help:
>>>>  	@echo " $(MAKE) check-block          Run block tests"
>>>>  	@echo " $(MAKE) check-tcg            Run TCG tests"
>>>>  	@echo " $(MAKE) check-report.html    Generates an HTML test report"
>>>> +	@echo " $(MAKE) check-venv           Creates a Python venv for tests"
>>>>  	@echo " $(MAKE) check-clean          Clean the tests"
>>>>  	@echo
>>>>  	@echo "Please note that HTML reports do not regenerate if the unit tests"
>>>> @@ -1017,6 +1018,24 @@ check-decodetree:
>>>>            ./check.sh "$(PYTHON)" "$(SRC_PATH)/scripts/decodetree.py", \
>>>>            TEST, decodetree.py)
>>>>  
>>>> +# Python venv for running tests
>>>> +
>>>> +.PHONY: check-venv
>>>> +
>>>> +TESTS_VENV_DIR=$(BUILD_DIR)/tests/venv
>>>> +TESTS_VENV_REQ=$(SRC_PATH)/tests/venv-requirements.txt
>>>> +
>>>> +$(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
>>>> +	$(call quiet-command, \
>>>> +            $(PYTHON) -m venv --system-site-packages $@, \
>>>> +            VENV, $@)
>>>> +	$(call quiet-command, \
>>>> +            $(TESTS_VENV_DIR)/bin/python -m pip -q install -r $(TESTS_VENV_REQ), \
>>>> +            PIP, $(TESTS_VENV_REQ))
>>>> +	$(call quiet-command, touch $@)
>>>
>>> Hmm maybe we should print something like:
>>>
>>>   "You can now activate this virtual environment using:
>>>     source $(TESTS_VENV_DIR)/tests/venv/bin/activate"
>>
>> I'm not sure this would be necessary: I expect usage of the venv
>> to be completely transparent.
>>
>> If we require people to learn what venv is and manually activate
>> it, I'd say we have failed to provide usable tools for running
>> the tests.
>>
> 
> Actually this is not necessary since the avocado is being called from
> the "venv python binary" as you can see in the check-acceptance target.
> 
> This way all the requirements installed in the test venv can be used
> without activating the virtual environment.

Well this is only true if you call 'make check-acceptance', not if you
want to filter tests, or run the single file you are working on...
Or am I missing something? The only option user-configurable (without
activating the venv) is the output of all tests via the AVOCADO_SHOW env
var.

This might be enough for a maintainer checking his subsystem, but I
don't find this practical for a acceptance test writer. And we want for
people to contribute adding tests, right?
Well, if we have maintainer running them, this is already a win :)

> 
>>
>>>
>>>> +
>>>> +check-venv: $(TESTS_VENV_DIR)
>>>> +
>>>>  # Consolidated targets
>>>>  
>>>>  .PHONY: check-qapi-schema check-qtest check-unit check check-clean
>>>> @@ -1030,6 +1049,7 @@ check-clean:
>>>>  	rm -rf $(check-unit-y) tests/*.o $(QEMU_IOTESTS_HELPERS-y)
>>>>  	rm -rf $(sort $(foreach target,$(SYSEMU_TARGET_LIST), $(check-qtest-$(target)-y)) $(check-qtest-generic-y))
>>>>  	rm -f tests/test-qapi-gen-timestamp
>>>> +	rm -rf $(TESTS_VENV_DIR)
>>>>  
>>>>  clean: check-clean
>>>>  
>>>> diff --git a/tests/venv-requirements.txt b/tests/venv-requirements.txt
>>>> new file mode 100644
>>>> index 0000000000..d39f9d1576
>>>> --- /dev/null
>>>> +++ b/tests/venv-requirements.txt
>>>> @@ -0,0 +1,3 @@
>>>> +# Add Python module requirements, one per line, to be installed
>>>> +# in the tests/venv Python virtual environment. For more info,
>>>> +# refer to: https://pip.pypa.io/en/stable/user_guide/#id1
>>>>
>>>
>>> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>
> 
>