diff mbox series

[v7,07/11] iotests: add findtests.py

Message ID 20210116134424.82867-8-vsementsov@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series Rework iotests/check | expand

Commit Message

Vladimir Sementsov-Ogievskiy Jan. 16, 2021, 1:44 p.m. UTC
Add python script with new logic of searching for tests:

Current ./check behavior:
 - tests are named [0-9][0-9][0-9]
 - tests must be registered in group file (even if test doesn't belong
   to any group, like 142)

Behavior of findtests.py:
 - group file is dropped
 - tests are all files in tests/ subdirectory (except for .out files),
   so it's not needed more to "register the test", just create it with
   appropriate name in tests/ subdirectory. Old names like
   [0-9][0-9][0-9] (in root iotests directory) are supported too, but
   not recommended for new tests
 - groups are parsed from '# group: ' line inside test files
 - optional file group.local may be used to define some additional
   groups for downstreams
 - 'disabled' group is used to temporary disable tests. So instead of
   commenting tests in old 'group' file you now can add them to
   disabled group with help of 'group.local' file
 - selecting test ranges like 5-15 are not supported more
   (to support restarting failed ./check command from the middle of the
    process, new argument is added: --start-from)

Benefits:
 - no rebase conflicts in group file on patch porting from branch to
   branch
 - no conflicts in upstream, when different series want to occupy same
   test number
 - meaningful names for test files
   For example, with digital number, when some person wants to add some
   test about block-stream, he most probably will just create a new
   test. But if there would be test-block-stream test already, he will
   at first look at it and may be just add a test-case into it.
   And anyway meaningful names are better.

This commit don't update check behavior (which will be done in further
commit), still, the documentation changed like new behavior is already
here.  Let's live with this small inconsistency for the following few
commits, until final change.

The file findtests.py is self-executable and may be used for debugging
purposes.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 docs/devel/testing.rst          |  50 +++++++++-
 tests/qemu-iotests/findtests.py | 159 ++++++++++++++++++++++++++++++++
 2 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 tests/qemu-iotests/findtests.py

Comments

Eric Blake Jan. 21, 2021, 4:18 p.m. UTC | #1
On 1/16/21 7:44 AM, Vladimir Sementsov-Ogievskiy wrote:
> Add python script with new logic of searching for tests:
> 
> Current ./check behavior:
>  - tests are named [0-9][0-9][0-9]
>  - tests must be registered in group file (even if test doesn't belong
>    to any group, like 142)
> 
> Behavior of findtests.py:
>  - group file is dropped
>  - tests are all files in tests/ subdirectory (except for .out files),
>    so it's not needed more to "register the test", just create it with
>    appropriate name in tests/ subdirectory. Old names like
>    [0-9][0-9][0-9] (in root iotests directory) are supported too, but
>    not recommended for new tests
>  - groups are parsed from '# group: ' line inside test files
>  - optional file group.local may be used to define some additional
>    groups for downstreams
>  - 'disabled' group is used to temporary disable tests. So instead of
>    commenting tests in old 'group' file you now can add them to
>    disabled group with help of 'group.local' file
>  - selecting test ranges like 5-15 are not supported more
>    (to support restarting failed ./check command from the middle of the
>     process, new argument is added: --start-from)
> 
> Benefits:
>  - no rebase conflicts in group file on patch porting from branch to
>    branch
>  - no conflicts in upstream, when different series want to occupy same
>    test number
>  - meaningful names for test files
>    For example, with digital number, when some person wants to add some
>    test about block-stream, he most probably will just create a new
>    test. But if there would be test-block-stream test already, he will
>    at first look at it and may be just add a test-case into it.
>    And anyway meaningful names are better.
> 
> This commit don't update check behavior (which will be done in further

doesn't

> commit), still, the documentation changed like new behavior is already
> here.  Let's live with this small inconsistency for the following few
> commits, until final change.
> 
> The file findtests.py is self-executable and may be used for debugging
> purposes.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  docs/devel/testing.rst          |  50 +++++++++-
>  tests/qemu-iotests/findtests.py | 159 ++++++++++++++++++++++++++++++++
>  2 files changed, 208 insertions(+), 1 deletion(-)
>  create mode 100644 tests/qemu-iotests/findtests.py
> 

> +++ b/tests/qemu-iotests/findtests.py

> +class TestFinder:
> +    def __init__(self, test_dir: Optional[str] = None) -> None:
> +        self.groups = defaultdict(set)
> +
> +        with chdir(test_dir):
> +            self.all_tests = glob.glob('[0-9][0-9][0-9]')
> +            self.all_tests += [f for f in glob.iglob('tests/*')
> +                               if not f.endswith('.out') and
> +                               os.path.isfile(f + '.out')]

Interesting that 'NNN' is a test even if 'NNN.out' is not present, but
'tests/NNN' is not.  Not sure if it is worth tweaking, though.


> +    def parse_test_name(self, name: str) -> str:
> +        if '/' in name:
> +            raise ValueError('Paths are unsupported for test selecting, '

selection

> +                             f'requiring "{name}" is wrong')
> +
> +        if re.fullmatch(r'\d+', name):
> +            # Numbered tests are old naming convetion. We should convert them

convention

> +            # to three-digit-length, like 1 --> 001.
> +            name = f'{int(name):03}'
> +        else:
> +            # Named tests all should be in tests/ subdirectory
> +            name = os.path.join('tests', name)
> +
> +        if name not in self.all_tests:
> +            raise ValueError(f'Test "{name}" is not found')
> +
> +        return name
> +
> +    def find_tests(self, groups: Optional[List[str]] = None,
> +                   exclude_groups: Optional[List[str]] = None,
> +                   tests: Optional[List[str]] = None,
> +                   start_from: Optional[str] = None) -> List[str]:

Reviewed-by: Eric Blake <eblake@redhat.com>
Eric Blake Jan. 21, 2021, 4:21 p.m. UTC | #2
On 1/16/21 7:44 AM, Vladimir Sementsov-Ogievskiy wrote:
> Add python script with new logic of searching for tests:
> 

> The file findtests.py is self-executable and may be used for debugging
> purposes.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---

> diff --git a/tests/qemu-iotests/findtests.py b/tests/qemu-iotests/findtests.py
> new file mode 100644
> index 0000000000..065ec13125
> --- /dev/null
> +++ b/tests/qemu-iotests/findtests.py
> @@ -0,0 +1,159 @@
> +# TestFinder class, define set of tests to run.

Per the commit message, the file is self-executable; doesn't that mean
it should have 755 permissions instead of 644, and have a #! python line?

> +        return sequence
> 

I guess it would also need a __main__ blurb at the end?  Or maybe I'm
misunderstanding the intent of the commit message line.
Vladimir Sementsov-Ogievskiy Jan. 21, 2021, 4:57 p.m. UTC | #3
21.01.2021 19:21, Eric Blake wrote:
> On 1/16/21 7:44 AM, Vladimir Sementsov-Ogievskiy wrote:
>> Add python script with new logic of searching for tests:
>>
> 
>> The file findtests.py is self-executable and may be used for debugging
>> purposes.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
> 
>> diff --git a/tests/qemu-iotests/findtests.py b/tests/qemu-iotests/findtests.py
>> new file mode 100644
>> index 0000000000..065ec13125
>> --- /dev/null
>> +++ b/tests/qemu-iotests/findtests.py
>> @@ -0,0 +1,159 @@
>> +# TestFinder class, define set of tests to run.
> 
> Per the commit message, the file is self-executable; doesn't that mean
> it should have 755 permissions instead of 644, and have a #! python line?
> 
>> +        return sequence
>>
> 
> I guess it would also need a __main__ blurb at the end?  Or maybe I'm
> misunderstanding the intent of the commit message line.
> 

These things are dropped recently and I forget to updated commit-msg.

So, what should be done is just drop this sentence from commit message.
Kevin Wolf Jan. 22, 2021, 11:48 a.m. UTC | #4
Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
> Add python script with new logic of searching for tests:
> 
> Current ./check behavior:
>  - tests are named [0-9][0-9][0-9]
>  - tests must be registered in group file (even if test doesn't belong
>    to any group, like 142)
> 
> Behavior of findtests.py:
>  - group file is dropped
>  - tests are all files in tests/ subdirectory (except for .out files),
>    so it's not needed more to "register the test", just create it with
>    appropriate name in tests/ subdirectory. Old names like
>    [0-9][0-9][0-9] (in root iotests directory) are supported too, but
>    not recommended for new tests
>  - groups are parsed from '# group: ' line inside test files
>  - optional file group.local may be used to define some additional
>    groups for downstreams
>  - 'disabled' group is used to temporary disable tests. So instead of
>    commenting tests in old 'group' file you now can add them to
>    disabled group with help of 'group.local' file
>  - selecting test ranges like 5-15 are not supported more
>    (to support restarting failed ./check command from the middle of the
>     process, new argument is added: --start-from)
> 
> Benefits:
>  - no rebase conflicts in group file on patch porting from branch to
>    branch
>  - no conflicts in upstream, when different series want to occupy same
>    test number
>  - meaningful names for test files
>    For example, with digital number, when some person wants to add some
>    test about block-stream, he most probably will just create a new
>    test. But if there would be test-block-stream test already, he will
>    at first look at it and may be just add a test-case into it.
>    And anyway meaningful names are better.
> 
> This commit don't update check behavior (which will be done in further
> commit), still, the documentation changed like new behavior is already
> here.  Let's live with this small inconsistency for the following few
> commits, until final change.
> 
> The file findtests.py is self-executable and may be used for debugging
> purposes.

As Eric mentioned, this isn't accurate any more.

You mentioned using it as a way to debug things. I assume this is now
covered by the dry run option?

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  docs/devel/testing.rst          |  50 +++++++++-
>  tests/qemu-iotests/findtests.py | 159 ++++++++++++++++++++++++++++++++
>  2 files changed, 208 insertions(+), 1 deletion(-)
>  create mode 100644 tests/qemu-iotests/findtests.py

> +    def add_group_file(self, fname: str) -> None:
> +        with open(fname) as f:
> +            for line in f:
> +                line = line.strip()
> +
> +                if (not line) or line[0] == '#':
> +                    continue
> +
> +                words = line.split()
> +                test_file = self.parse_test_name(words[0])
> +                groups = words[1:]

The previous version still had this:

+                if test_file not in self.all_tests:
+                    print(f'Warning: {fname}: "{test_file}" test is not found.'
+                          ' Skip.')
+                    continue

Why did you remove it? I found this useful when I had a wrong test name
in my group.local. Now it's silently ignored.

> +                for g in groups:
> +                    self.groups[g].add(test_file)

Kevin
Kevin Wolf Jan. 22, 2021, 11:49 a.m. UTC | #5
Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
> +        if 'disabled' not in groups and 'disabled' not in exclude_groups:
> +            # Don't want to modify function argument, so create new list.
> +            exclude_groups = exclude_groups + ['disabled']

Oops, forgot the other comment I wanted to make:

This would only have been needed if you had turned exclude_groups into a
Sequence. Now that it's still a list, copying the list isn't strictly
necessary.

Kevin
Vladimir Sementsov-Ogievskiy Jan. 22, 2021, 11:57 a.m. UTC | #6
22.01.2021 14:48, Kevin Wolf wrote:
> Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> Add python script with new logic of searching for tests:
>>
>> Current ./check behavior:
>>   - tests are named [0-9][0-9][0-9]
>>   - tests must be registered in group file (even if test doesn't belong
>>     to any group, like 142)
>>
>> Behavior of findtests.py:
>>   - group file is dropped
>>   - tests are all files in tests/ subdirectory (except for .out files),
>>     so it's not needed more to "register the test", just create it with
>>     appropriate name in tests/ subdirectory. Old names like
>>     [0-9][0-9][0-9] (in root iotests directory) are supported too, but
>>     not recommended for new tests
>>   - groups are parsed from '# group: ' line inside test files
>>   - optional file group.local may be used to define some additional
>>     groups for downstreams
>>   - 'disabled' group is used to temporary disable tests. So instead of
>>     commenting tests in old 'group' file you now can add them to
>>     disabled group with help of 'group.local' file
>>   - selecting test ranges like 5-15 are not supported more
>>     (to support restarting failed ./check command from the middle of the
>>      process, new argument is added: --start-from)
>>
>> Benefits:
>>   - no rebase conflicts in group file on patch porting from branch to
>>     branch
>>   - no conflicts in upstream, when different series want to occupy same
>>     test number
>>   - meaningful names for test files
>>     For example, with digital number, when some person wants to add some
>>     test about block-stream, he most probably will just create a new
>>     test. But if there would be test-block-stream test already, he will
>>     at first look at it and may be just add a test-case into it.
>>     And anyway meaningful names are better.
>>
>> This commit don't update check behavior (which will be done in further
>> commit), still, the documentation changed like new behavior is already
>> here.  Let's live with this small inconsistency for the following few
>> commits, until final change.
>>
>> The file findtests.py is self-executable and may be used for debugging
>> purposes.
> 
> As Eric mentioned, this isn't accurate any more.
> 
> You mentioned using it as a way to debug things. I assume this is now
> covered by the dry run option?

yes

> 
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   docs/devel/testing.rst          |  50 +++++++++-
>>   tests/qemu-iotests/findtests.py | 159 ++++++++++++++++++++++++++++++++
>>   2 files changed, 208 insertions(+), 1 deletion(-)
>>   create mode 100644 tests/qemu-iotests/findtests.py
> 
>> +    def add_group_file(self, fname: str) -> None:
>> +        with open(fname) as f:
>> +            for line in f:
>> +                line = line.strip()
>> +
>> +                if (not line) or line[0] == '#':
>> +                    continue
>> +
>> +                words = line.split()
>> +                test_file = self.parse_test_name(words[0])
>> +                groups = words[1:]
> 
> The previous version still had this:
> 
> +                if test_file not in self.all_tests:
> +                    print(f'Warning: {fname}: "{test_file}" test is not found.'
> +                          ' Skip.')
> +                    continue
> 
> Why did you remove it? I found this useful when I had a wrong test name
> in my group.local. Now it's silently ignored.


Because now we use parse_test_name which will raise ValueError, so we will not go to this if anyway.

So, wrong name will not be silently ignored, check will fail, and you'll have to fix group file.. It is suitable?

> 
>> +                for g in groups:
>> +                    self.groups[g].add(test_file)
> 
> Kevin
>
Vladimir Sementsov-Ogievskiy Jan. 22, 2021, 11:59 a.m. UTC | #7
22.01.2021 14:49, Kevin Wolf wrote:
> Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> +        if 'disabled' not in groups and 'disabled' not in exclude_groups:
>> +            # Don't want to modify function argument, so create new list.
>> +            exclude_groups = exclude_groups + ['disabled']
> 
> Oops, forgot the other comment I wanted to make:
> 
> This would only have been needed if you had turned exclude_groups into a
> Sequence. Now that it's still a list, copying the list isn't strictly
> necessary.
> 

I just think that such side effects (changing function arguments when it is not part of function intention) are better to avoid.
Kevin Wolf Jan. 22, 2021, 12:45 p.m. UTC | #8
Am 22.01.2021 um 12:57 hat Vladimir Sementsov-Ogievskiy geschrieben:
> 22.01.2021 14:48, Kevin Wolf wrote:
> > Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
> > > +    def add_group_file(self, fname: str) -> None:
> > > +        with open(fname) as f:
> > > +            for line in f:
> > > +                line = line.strip()
> > > +
> > > +                if (not line) or line[0] == '#':
> > > +                    continue
> > > +
> > > +                words = line.split()
> > > +                test_file = self.parse_test_name(words[0])
> > > +                groups = words[1:]
> > 
> > The previous version still had this:
> > 
> > +                if test_file not in self.all_tests:
> > +                    print(f'Warning: {fname}: "{test_file}" test is not found.'
> > +                          ' Skip.')
> > +                    continue
> > 
> > Why did you remove it? I found this useful when I had a wrong test name
> > in my group.local. Now it's silently ignored.
> 
> 
> Because now we use parse_test_name which will raise ValueError, so we
> will not go to this if anyway.
> 
> So, wrong name will not be silently ignored, check will fail, and
> you'll have to fix group file.. It is suitable?

It doesn't, though.

Oh, wait... Is it possible that you lost support for group.local
altogether? grep for "group.local" comes up empty, and add_group_file()
is only defined, but never called.

So the reason for the behaviour seems to be that it doesn't even try to
parse the group file.

Kevin
Vladimir Sementsov-Ogievskiy Jan. 22, 2021, 1:16 p.m. UTC | #9
22.01.2021 15:45, Kevin Wolf wrote:
> Am 22.01.2021 um 12:57 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> 22.01.2021 14:48, Kevin Wolf wrote:
>>> Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
>>>> +    def add_group_file(self, fname: str) -> None:
>>>> +        with open(fname) as f:
>>>> +            for line in f:
>>>> +                line = line.strip()
>>>> +
>>>> +                if (not line) or line[0] == '#':
>>>> +                    continue
>>>> +
>>>> +                words = line.split()
>>>> +                test_file = self.parse_test_name(words[0])
>>>> +                groups = words[1:]
>>>
>>> The previous version still had this:
>>>
>>> +                if test_file not in self.all_tests:
>>> +                    print(f'Warning: {fname}: "{test_file}" test is not found.'
>>> +                          ' Skip.')
>>> +                    continue
>>>
>>> Why did you remove it? I found this useful when I had a wrong test name
>>> in my group.local. Now it's silently ignored.
>>
>>
>> Because now we use parse_test_name which will raise ValueError, so we
>> will not go to this if anyway.
>>
>> So, wrong name will not be silently ignored, check will fail, and
>> you'll have to fix group file.. It is suitable?
> 
> It doesn't, though.
> 
> Oh, wait... Is it possible that you lost support for group.local
> altogether? grep for "group.local" comes up empty, and add_group_file()
> is only defined, but never called.
> 
> So the reason for the behaviour seems to be that it doesn't even try to
> parse the group file.
> 

Ooops, you are right :( I've dropped an extra layer of indirection to make things simpler and group.local was lost. It's the reason to send v8, I'll do it now.

In a mean time, reverting 06 for now is OK for me.
Kevin Wolf Jan. 22, 2021, 1:34 p.m. UTC | #10
Am 22.01.2021 um 14:16 hat Vladimir Sementsov-Ogievskiy geschrieben:
> 22.01.2021 15:45, Kevin Wolf wrote:
> > Am 22.01.2021 um 12:57 hat Vladimir Sementsov-Ogievskiy geschrieben:
> > > 22.01.2021 14:48, Kevin Wolf wrote:
> > > > Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
> > > > > +    def add_group_file(self, fname: str) -> None:
> > > > > +        with open(fname) as f:
> > > > > +            for line in f:
> > > > > +                line = line.strip()
> > > > > +
> > > > > +                if (not line) or line[0] == '#':
> > > > > +                    continue
> > > > > +
> > > > > +                words = line.split()
> > > > > +                test_file = self.parse_test_name(words[0])
> > > > > +                groups = words[1:]
> > > > 
> > > > The previous version still had this:
> > > > 
> > > > +                if test_file not in self.all_tests:
> > > > +                    print(f'Warning: {fname}: "{test_file}" test is not found.'
> > > > +                          ' Skip.')
> > > > +                    continue
> > > > 
> > > > Why did you remove it? I found this useful when I had a wrong test name
> > > > in my group.local. Now it's silently ignored.
> > > 
> > > 
> > > Because now we use parse_test_name which will raise ValueError, so we
> > > will not go to this if anyway.
> > > 
> > > So, wrong name will not be silently ignored, check will fail, and
> > > you'll have to fix group file.. It is suitable?
> > 
> > It doesn't, though.
> > 
> > Oh, wait... Is it possible that you lost support for group.local
> > altogether? grep for "group.local" comes up empty, and add_group_file()
> > is only defined, but never called.
> > 
> > So the reason for the behaviour seems to be that it doesn't even try to
> > parse the group file.
> 
> Ooops, you are right :( I've dropped an extra layer of indirection to
> make things simpler and group.local was lost. It's the reason to send
> v8, I'll do it now.

You can wait with sending v8 until I've completed review in case
something else comes up. So far I'm done with the changes to the part
that I reviewed last time and apart from this bug they look good to me.
Now it's the remaining patches.

> In a mean time, reverting 06 for now is OK for me.

Not a big deal if we get it fixed soon, it only becomes a problem if the
rest of this series gets shelved for a longer time. Maybe we can
complete it today, maybe on Monday, and then I'll send a pull request
right away.

Kevin
Vladimir Sementsov-Ogievskiy Jan. 22, 2021, 1:52 p.m. UTC | #11
22.01.2021 16:34, Kevin Wolf wrote:
> Am 22.01.2021 um 14:16 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> 22.01.2021 15:45, Kevin Wolf wrote:
>>> Am 22.01.2021 um 12:57 hat Vladimir Sementsov-Ogievskiy geschrieben:
>>>> 22.01.2021 14:48, Kevin Wolf wrote:
>>>>> Am 16.01.2021 um 14:44 hat Vladimir Sementsov-Ogievskiy geschrieben:
>>>>>> +    def add_group_file(self, fname: str) -> None:
>>>>>> +        with open(fname) as f:
>>>>>> +            for line in f:
>>>>>> +                line = line.strip()
>>>>>> +
>>>>>> +                if (not line) or line[0] == '#':
>>>>>> +                    continue
>>>>>> +
>>>>>> +                words = line.split()
>>>>>> +                test_file = self.parse_test_name(words[0])
>>>>>> +                groups = words[1:]
>>>>>
>>>>> The previous version still had this:
>>>>>
>>>>> +                if test_file not in self.all_tests:
>>>>> +                    print(f'Warning: {fname}: "{test_file}" test is not found.'
>>>>> +                          ' Skip.')
>>>>> +                    continue
>>>>>
>>>>> Why did you remove it? I found this useful when I had a wrong test name
>>>>> in my group.local. Now it's silently ignored.
>>>>
>>>>
>>>> Because now we use parse_test_name which will raise ValueError, so we
>>>> will not go to this if anyway.
>>>>
>>>> So, wrong name will not be silently ignored, check will fail, and
>>>> you'll have to fix group file.. It is suitable?
>>>
>>> It doesn't, though.
>>>
>>> Oh, wait... Is it possible that you lost support for group.local
>>> altogether? grep for "group.local" comes up empty, and add_group_file()
>>> is only defined, but never called.
>>>
>>> So the reason for the behaviour seems to be that it doesn't even try to
>>> parse the group file.
>>
>> Ooops, you are right :( I've dropped an extra layer of indirection to
>> make things simpler and group.local was lost. It's the reason to send
>> v8, I'll do it now.
> 
> You can wait with sending v8 until I've completed review in case
> something else comes up. So far I'm done with the changes to the part
> that I reviewed last time and apart from this bug they look good to me.
> Now it's the remaining patches.

OK. This thing is to be fixed in [10], not here, I'll send a squash-in

> 
>> In a mean time, reverting 06 for now is OK for me.
> 
> Not a big deal if we get it fixed soon, it only becomes a problem if the
> rest of this series gets shelved for a longer time. Maybe we can
> complete it today, maybe on Monday, and then I'll send a pull request
> right away.
> 
> Kevin
>
diff mbox series

Patch

diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
index 0aa7a13bba..454b706141 100644
--- a/docs/devel/testing.rst
+++ b/docs/devel/testing.rst
@@ -111,7 +111,7 @@  check-block
 -----------
 
 ``make check-block`` runs a subset of the block layer iotests (the tests that
-are in the "auto" group in ``tests/qemu-iotests/group``).
+are in the "auto" group).
 See the "QEMU iotests" section below for more information.
 
 GCC gcov support
@@ -224,6 +224,54 @@  another application on the host may have locked the file, possibly leading to a
 test failure.  If using such devices are explicitly desired, consider adding
 ``locking=off`` option to disable image locking.
 
+Test case groups
+----------------
+
+"Tests may belong to one or more test groups, which are defined in the form
+of a comment in the test source file. By convention, test groups are listed
+in the second line of the test file, after the "#!/..." line, like this:
+
+.. code::
+
+  #!/usr/bin/env python3
+  # group: auto quick
+  #
+  ...
+
+Another way of defining groups is creating the tests/qemu-iotests/group.local
+file. This should be used only for downstream (this file should never appear
+in upstream). This file may be used for defining some downstream test groups
+or for temporarily disabling tests, like this:
+
+.. code::
+
+  # groups for some company downstream process
+  #
+  # ci - tests to run on build
+  # down - our downstream tests, not for upstream
+  #
+  # Format of each line is:
+  # TEST_NAME TEST_GROUP [TEST_GROUP ]...
+
+  013 ci
+  210 disabled
+  215 disabled
+  our-ugly-workaround-test down ci
+
+Note that the following group names have a special meaning:
+
+- quick: Tests in this group should finish within a few seconds.
+
+- auto: Tests in this group are used during "make check" and should be
+  runnable in any case. That means they should run with every QEMU binary
+  (also non-x86), with every QEMU configuration (i.e. must not fail if
+  an optional feature is not compiled in - but reporting a "skip" is ok),
+  work at least with the qcow2 file format, work with all kind of host
+  filesystems and users (e.g. "nobody" or "root") and must not take too
+  much memory and disk space (since CI pipelines tend to fail otherwise).
+
+- disabled: Tests in this group are disabled and ignored by check.
+
 .. _docker-ref:
 
 Docker based tests
diff --git a/tests/qemu-iotests/findtests.py b/tests/qemu-iotests/findtests.py
new file mode 100644
index 0000000000..065ec13125
--- /dev/null
+++ b/tests/qemu-iotests/findtests.py
@@ -0,0 +1,159 @@ 
+# TestFinder class, define set of tests to run.
+#
+# Copyright (c) 2020-2021 Virtuozzo International GmbH
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import glob
+import re
+from collections import defaultdict
+from contextlib import contextmanager
+from typing import Optional, List, Iterator, Set
+
+
+@contextmanager
+def chdir(path: Optional[str] = None) -> Iterator[None]:
+    if path is None:
+        yield
+        return
+
+    saved_dir = os.getcwd()
+    os.chdir(path)
+    try:
+        yield
+    finally:
+        os.chdir(saved_dir)
+
+
+class TestFinder:
+    def __init__(self, test_dir: Optional[str] = None) -> None:
+        self.groups = defaultdict(set)
+
+        with chdir(test_dir):
+            self.all_tests = glob.glob('[0-9][0-9][0-9]')
+            self.all_tests += [f for f in glob.iglob('tests/*')
+                               if not f.endswith('.out') and
+                               os.path.isfile(f + '.out')]
+
+            for t in self.all_tests:
+                with open(t) as f:
+                    for line in f:
+                        if line.startswith('# group: '):
+                            for g in line.split()[2:]:
+                                self.groups[g].add(t)
+                            break
+
+    def add_group_file(self, fname: str) -> None:
+        with open(fname) as f:
+            for line in f:
+                line = line.strip()
+
+                if (not line) or line[0] == '#':
+                    continue
+
+                words = line.split()
+                test_file = self.parse_test_name(words[0])
+                groups = words[1:]
+
+                for g in groups:
+                    self.groups[g].add(test_file)
+
+    def parse_test_name(self, name: str) -> str:
+        if '/' in name:
+            raise ValueError('Paths are unsupported for test selecting, '
+                             f'requiring "{name}" is wrong')
+
+        if re.fullmatch(r'\d+', name):
+            # Numbered tests are old naming convetion. We should convert them
+            # to three-digit-length, like 1 --> 001.
+            name = f'{int(name):03}'
+        else:
+            # Named tests all should be in tests/ subdirectory
+            name = os.path.join('tests', name)
+
+        if name not in self.all_tests:
+            raise ValueError(f'Test "{name}" is not found')
+
+        return name
+
+    def find_tests(self, groups: Optional[List[str]] = None,
+                   exclude_groups: Optional[List[str]] = None,
+                   tests: Optional[List[str]] = None,
+                   start_from: Optional[str] = None) -> List[str]:
+        """Find tests
+
+        Algorithm:
+
+        1. a. if some @groups specified
+             a.1 Take all tests from @groups
+             a.2 Drop tests, which are in at least one of @exclude_groups or in
+                 'disabled' group (if 'disabled' is not listed in @groups)
+             a.3 Add tests from @tests (don't exclude anything from them)
+
+           b. else, if some @tests specified:
+             b.1 exclude_groups must be not specified, so just take @tests
+
+           c. else (only @exclude_groups list is non-empty):
+             c.1 Take all tests
+             c.2 Drop tests, which are in at least one of @exclude_groups or in
+                 'disabled' group
+
+        2. sort
+
+        3. If start_from specified, drop tests from first one to @start_from
+           (not inclusive)
+        """
+        if groups is None:
+            groups = []
+        if exclude_groups is None:
+            exclude_groups = []
+        if tests is None:
+            tests = []
+
+        res: Set[str] = set()
+        if groups:
+            # Some groups specified. exclude_groups supported, additionally
+            # selecting some individual tests supported as well.
+            res.update(*(self.groups[g] for g in groups))
+        elif tests:
+            # Some individual tests specified, but no groups. In this case
+            # we don't support exclude_groups.
+            if exclude_groups:
+                raise ValueError("Can't exclude from individually specified "
+                                 "tests.")
+        else:
+            # No tests no groups: start from all tests, exclude_groups
+            # supported.
+            res.update(self.all_tests)
+
+        if 'disabled' not in groups and 'disabled' not in exclude_groups:
+            # Don't want to modify function argument, so create new list.
+            exclude_groups = exclude_groups + ['disabled']
+
+        res = res.difference(*(self.groups[g] for g in exclude_groups))
+
+        # We want to add @tests. But for compatibility with old test names,
+        # we should convert any number < 100 to number padded by
+        # leading zeroes, like 1 -> 001 and 23 -> 023.
+        for t in tests:
+            res.add(self.parse_test_name(t))
+
+        sequence = sorted(res)
+
+        if start_from is not None:
+            del sequence[:sequence.index(self.parse_test_name(start_from))]
+
+        return sequence