[PATCH v3 06/10] iotests: add testfinder.py

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

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 new test:
 - group file is dropped
 - tests are searched by file-name instead of group file, so it's not
   needed more to "register the test", just create it with name
   *-test. Old names like [0-9][0-9][0-9] 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

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 just adds class, which is unused now, and will be used in
further patches, to finally substitute ./check selecting tests logic.

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.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 docs/devel/testing.rst           |  52 +++++++++-
 tests/qemu-iotests/testfinder.py | 167 +++++++++++++++++++++++++++++++
 2 files changed, 218 insertions(+), 1 deletion(-)
 create mode 100755 tests/qemu-iotests/testfinder.py

diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
index 770a987ea4..6c9d5b126b 100644
--- a/docs/devel/testing.rst
+++ b/docs/devel/testing.rst
@@ -153,7 +153,7 @@ 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
@@ -267,6 +267,56 @@ 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
+----------------
+
+Test may belong to some groups, you may define it in the comment inside the
+test. By convention, test groups are listed in the second line of the test
+file, after "#!/..." line, like this:
+
+.. code::
+
+  #!/usr/bin/env python3
+  # group: auto quick
+  #
+  ...
+
+Additional way of defining groups is creating 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 temporary disable 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
+
+The following groups are defined:
+
+- quick : Tests in this group should finish within some few seconds.
+
+- img : Tests in this group can be used to excercise the qemu-img tool.
+
+- 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/testfinder.py b/tests/qemu-iotests/testfinder.py
new file mode 100755
index 0000000000..1da28564c0
--- /dev/null
+++ b/tests/qemu-iotests/testfinder.py
@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+#
+# Parse command line options to define set of tests to run.
+#
+# Copyright (c) 2020 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 sys
+import glob
+import argparse
+import re
+from collections import defaultdict
+from contextlib import contextmanager
+
+
+@contextmanager
+def chdir(path):
+    if path is None:
+        yield
+        return
+
+    saved_dir = os.getcwd()
+    os.chdir(path)
+    try:
+        yield
+    finally:
+        os.chdir(saved_dir)
+
+
+class TestFinder:
+    @staticmethod
+    def create_argparser():
+        p = argparse.ArgumentParser(description="Select set of tests",
+                                    add_help=False, usage=argparse.SUPPRESS)
+
+        p.add_argument('-g', metavar='group1,...', dest='groups',
+                       help='include tests from these groups')
+        p.add_argument('-x', metavar='group1,...', dest='exclude_groups',
+                       help='exclude tests from these groups')
+        p.add_argument('tests', metavar='TEST_FILES', nargs='*',
+                       help='tests to run')
+
+        return p
+
+    argparser = create_argparser.__func__()
+
+    def __init__(self, test_dir=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('*-test')]
+
+            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)
+
+    def add_group_file(self, fname):
+        with open(fname) as f:
+            for line in f:
+                line = line.strip()
+
+                if (not line) or line[0] == '#':
+                    continue
+
+                words = line.split()
+                test_file = words[0]
+                groups = words[1:]
+
+                if test_file not in self.all_tests:
+                    print('Warning: {}: "{}" test is not found. '
+                          'Skip.'.format(fname, test_file))
+                    continue
+
+                for g in groups:
+                    self.groups[g].add(test_file)
+
+    def find_tests(self, groups=None, exclude_groups=None, tests=None):
+        """
+        1. Take all tests from @groups,
+           or just all tests if @groups is None and @tests is None
+           or nothing if @groups is None and @tests is not None
+        2. Drop tests, which are in at least one of @exclude_groups or in
+           'disabled' group (if 'disabled' is not listed in @groups)
+        3. Add tests from @tests
+        """
+        if groups is None:
+            groups = []
+        if exclude_groups is None:
+            exclude_groups = []
+        if tests is None:
+            tests = []
+
+        if groups:
+            res = set().union(*(self.groups[g] for g in groups))
+        elif tests:
+            res = set()
+        else:
+            res = set(self.all_tests)
+
+        if 'disabled' not in groups and 'disabled' not in exclude_groups:
+            exclude_groups.append('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:
+            if re.fullmatch(r'\d{1,2}', t):
+                res.add('0' * (3 - len(t)) + t)
+            else:
+                res.add(t)
+
+        return sorted(res)
+
+    def find_tests_argv(self, argv):
+        args, remaining = self.argparser.parse_known_args(argv)
+
+        if args.groups is not None:
+            args.groups = args.groups.split(',')
+
+        if args.exclude_groups is not None:
+            args.exclude_groups = args.exclude_groups.split(',')
+
+        return self.find_tests(**vars(args)), remaining
+
+
+def find_tests(argv, test_dir=None):
+    tf = TestFinder(test_dir)
+
+    if test_dir is None:
+        group_local = 'group.local'
+    else:
+        group_local = os.path.join(test_dir, 'group.local')
+    if os.path.isfile(group_local):
+        tf.add_group_file(group_local)
+
+    return tf.find_tests_argv(argv)
+
+
+if __name__ == '__main__':
+    if len(sys.argv) == 2 and sys.argv[1] in ['-h', '--help']:
+        TestFinder.argparser.print_help()
+        exit()
+
+    tests, remaining_argv = find_tests(sys.argv[1:])
+    print('\n'.join(tests))
+    if remaining_argv:
+        print('\nUnhandled options: ', remaining_argv)
-- 
2.21.0