[6.15.z] Add pytest option to randomly select and run number/percenta…

…ge of tests from the collection. (#15554)

Co-authored-by: Jameer Pathan <[email protected]>

conftest.py

@@ -23,6 +23,7 @@
     'pytest_plugins.sanity_plugin',
     'pytest_plugins.video_cleanup',
     'pytest_plugins.jira_comments',
+    'pytest_plugins.select_random_tests',
     'pytest_plugins.capsule_n-minus',
     # Fixtures
     'pytest_fixtures.core.broker',

pytest_plugins/select_random_tests.py

@@ -0,0 +1,69 @@
+import math
+import random
+
+from fauxfactory import gen_string
+import pytest
+
+from robottelo.logging import logger
+
+
+def pytest_addoption(parser):
+    """Add --select-random-tests option to select and run N random tests from the selected test collection.
+    Examples:
+        pytest tests/foreman/ --select-random-tests 4 --random-seed fksdjn
+        pytest tests/foreman/ --select-random-tests '5%'
+    """
+    parser.addoption(
+        '--select-random-tests',
+        action='store',
+        default=0,
+        help='Number/Percentage of tests to randomly select and run from selected test collection. \n '
+        'To re-run same collection later, provide seed value using --random-seed. '
+        'OR check robottelo.log to get the seed value that was generated randomly.',
+    )
+    parser.addoption(
+        '--random-seed',
+        action='store',
+        default=gen_string('alpha'),
+        help='Seed value for random test collection. Should be used with --select-random-tests option.',
+    )
+
+
+def pytest_configure(config):
+    """Register select_random_tests and random_seed markers to avoid warnings."""
+    markers = [
+        'select_random_tests: Number/Percentage of tests to randomly select and run.',
+        'random_seed: Seed value for random test collection.',
+    ]
+    for marker in markers:
+        config.addinivalue_line('markers', marker)
+
+
+@pytest.hookimpl(trylast=True)
+def pytest_collection_modifyitems(items, config):
+    """Modify test collection to select and run N random tests from the selected test collection."""
+    select_random_tests = config.getoption('select_random_tests')
+    random_seed = config.getoption('random_seed')
+    if select_random_tests:
+        select_random_tests = (
+            math.ceil(len(items) * float(select_random_tests.split('%')[0]) / 100)
+            if '%' in select_random_tests
+            else int(select_random_tests)
+        )
+        try:
+            random.seed(random_seed)
+            selected = random.sample(items, k=select_random_tests)
+        except ValueError as err:
+            logger.warning(
+                'Number of tests to select randomly are greater than the tests in the selected collection. '
+                f'Tests collected: {len(items)}, Tests to select randomly: {select_random_tests}, Seed value: {random_seed}'
+            )
+            raise err
+        logger.info(
+            'Modifying test collection based on --select-random-tests pytest option. '
+            f'Tests collected: {len(items)}, Tests to select randomly: {select_random_tests}, Seed value: {random_seed}'
+        )
+        deselected = [item for item in items if item not in selected]
+        # selected will be empty if no filter option was passed, defaulting to full items list
+        items[:] = selected if deselected else items
+        config.hook.pytest_deselected(items=deselected)