twister: pytest: Add --pytest-args to Twister command line

Extend Twister command line with --pytest-args. This parameter
is passed to pytest subprocess. It allows to select a specific
testcase from a test suite.

Signed-off-by: Grzegorz Chwierut <grzegorz.chwierut@nordicsemi.no>

doc/develop/test/pytest.rst

@@ -56,6 +56,16 @@ Pytest scans the given locations looking for tests, following its default
 `discovery rules <https://docs.pytest.org/en/7.1.x/explanation/goodpractices.html#conventions-for-python-test-discovery>`_
 One can also pass some extra arguments to the pytest from yaml file using ``pytest_args`` keyword
 under ``harness_config``, e.g.: ``pytest_args: [‘-k=test_method’, ‘--log-level=DEBUG’]``.
+There is also an option to pass ``--pytest-args`` through Twister command line parameters.
+This can be particularly useful when one wants to select a specific testcase from a test suite.
+For instance, one can use a command:
+
+.. code-block:: console
+
+   $ ./scripts/twister --platform native_sim -T samples/subsys/testsuite/pytest/shell \
+   -s samples/subsys/testsuite/pytest/shell/sample.pytest.shell \
+   --pytest-args='-k test_shell_print_version'
+
 
 Helpers & fixtures
 ==================

scripts/pylib/twister/twisterlib/environment.py

@@ -216,6 +216,11 @@ Artificially long but functional example:
         and 'fifo_loop' is a name of a function found in main.c without test prefix.
         """)
 
+    parser.add_argument("--pytest-args",
+        help="""Pass additional arguments to the pytest subprocess. This parameter
+        will override the pytest_args from the harness_config in YAML file.
+        """)
+
     valgrind_asan_group.add_argument(
         "--enable-valgrind", action="store_true",
         help="""Run binary through valgrind and check for several memory access

scripts/pylib/twister/twisterlib/harness.py

@@ -309,8 +309,9 @@ class Pytest(Harness):
 
     def generate_command(self):
         config = self.instance.testsuite.harness_config
+        handler: Handler = self.instance.handler
         pytest_root = config.get('pytest_root', ['pytest']) if config else ['pytest']
-        pytest_args = config.get('pytest_args', []) if config else []
+        pytest_args_yaml = config.get('pytest_args', []) if config else []
         pytest_dut_scope = config.get('pytest_dut_scope', None) if config else None
         command = [
             'pytest',
@@ -324,12 +325,19 @@ class Pytest(Harness):
         ]
         command.extend([os.path.normpath(os.path.join(
             self.source_dir, os.path.expanduser(os.path.expandvars(src)))) for src in pytest_root])
-        command.extend(pytest_args)
+
+        if handler.options.pytest_args:
+            command.append(handler.options.pytest_args)
+            if pytest_args_yaml:
+                logger.warning(f'The pytest_args ({handler.options.pytest_args}) specified '
+                               'in the command line will override the pytest_args defined '
+                               f'in the YAML file {pytest_args_yaml}')
+        else:
+            command.extend(pytest_args_yaml)
+
         if pytest_dut_scope:
             command.append(f'--dut-scope={pytest_dut_scope}')
 
-        handler: Handler = self.instance.handler
-
         if handler.options.verbose > 1:
             command.extend([
                 '--log-cli-level=DEBUG',
@@ -489,6 +497,9 @@ class Pytest(Harness):
                         tc.status = 'error'
                     tc.reason = elem.get('message')
                     tc.output = elem.text
+        else:
+            self.state = 'skipped'
+            self.instance.reason = 'No tests collected'
 
 
 class Gtest(Harness):

scripts/tests/twister/pytest_integration/test_harness_pytest.py

@@ -25,6 +25,7 @@ def testinstance() -> TestInstance:
     testinstance.handler = mock.Mock()
     testinstance.handler.options = mock.Mock()
     testinstance.handler.options.verbose = 1
+    testinstance.handler.options.pytest_args = None
     testinstance.handler.type_str = 'native'
     return testinstance
 
@@ -67,6 +68,18 @@ def test_pytest_command_extra_args(testinstance: TestInstance):
         assert c in command
 
 
+def test_pytest_command_extra_args_in_options(testinstance: TestInstance):
+    pytest_harness = Pytest()
+    pytest_args_from_yaml = '-k test_from_yaml'
+    pytest_args_from_cmd = '-k test_from_cmd'
+    testinstance.testsuite.harness_config['pytest_args'] = [pytest_args_from_yaml]
+    testinstance.handler.options.pytest_args = pytest_args_from_cmd
+    pytest_harness.configure(testinstance)
+    command = pytest_harness.generate_command()
+    assert pytest_args_from_cmd in command
+    assert pytest_args_from_yaml not in command
+
+
 @pytest.mark.parametrize(
     ('pytest_root', 'expected'),
     [
@@ -222,3 +235,56 @@ def test_if_report_with_skip(pytester, testinstance: TestInstance):
     assert len(testinstance.testcases) == 2
     for tc in testinstance.testcases:
         assert tc.status == "skipped"
+
+
+def test_if_report_with_filter(pytester, testinstance: TestInstance):
+    test_file_content = textwrap.dedent("""
+        import pytest
+        def test_A():
+            pass
+        def test_B():
+            pass
+    """)
+    test_file = pytester.path / 'test_filter.py'
+    test_file.write_text(test_file_content)
+    report_file = pytester.path / 'report.xml'
+    result = pytester.runpytest(
+        str(test_file),
+        '-k', 'test_B',
+        f'--junit-xml={str(report_file)}'
+    )
+    result.assert_outcomes(passed=1)
+    assert report_file.is_file()
+
+    pytest_harness = Pytest()
+    pytest_harness.configure(testinstance)
+    pytest_harness.report_file = report_file
+    pytest_harness._update_test_status()
+    assert pytest_harness.state == "passed"
+    assert testinstance.status == "passed"
+    assert len(testinstance.testcases) == 1
+
+
+def test_if_report_with_no_collected(pytester, testinstance: TestInstance):
+    test_file_content = textwrap.dedent("""
+        import pytest
+        def test_A():
+            pass
+    """)
+    test_file = pytester.path / 'test_filter.py'
+    test_file.write_text(test_file_content)
+    report_file = pytester.path / 'report.xml'
+    result = pytester.runpytest(
+        str(test_file),
+        '-k', 'test_B',
+        f'--junit-xml={str(report_file)}'
+    )
+    result.assert_outcomes(passed=0)
+    assert report_file.is_file()
+
+    pytest_harness = Pytest()
+    pytest_harness.configure(testinstance)
+    pytest_harness.report_file = report_file
+    pytest_harness._update_test_status()
+    assert pytest_harness.state == "skipped"
+    assert testinstance.status == "skipped"