twister: harness: introduce shell harness

Introduce a new harness based on pytest that does basic shell command
handling. The harness is enabeld using:

harness: shell

and expects a file with parameters in the form:

test_shell_harness:
- command: "kernel version"
  expected: "Zephyr version .*"
- ...

Multiple commands and their expected output can be tested.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/pylib/shell-twister-harness/conftest.py

@@ -0,0 +1,7 @@
+# Copyright (c) 2025 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+
+def pytest_addoption(parser):
+    parser.addoption('--testdata')

scripts/pylib/shell-twister-harness/test_shell.py

@@ -0,0 +1,36 @@
+# Copyright (c) 2025 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+import logging
+import re
+
+import pytest
+import yaml
+from twister_harness import Shell
+
+logger = logging.getLogger(__name__)
+
+
+@pytest.fixture
+def testdata_path(request):
+    return request.config.getoption("--testdata")
+
+
+def get_next_commands(testdata_path):
+    with open(testdata_path) as yaml_file:
+        data = yaml.safe_load(yaml_file)
+    for entry in data['test_shell_harness']:
+        yield entry['command'], entry['expected']
+
+
+def test_shell_harness(shell: Shell, testdata_path):
+    for command, expected in get_next_commands(testdata_path):
+        logger.info('send command: %s', command)
+        lines = shell.exec_command(command)
+        match = False
+        for line in lines:
+            if re.match(expected, line):
+                match = True
+                break
+        assert match, 'expected response not found'
+        logger.info('response is valid')

scripts/pylib/twister/twisterlib/harness.py

@@ -403,6 +403,7 @@ class Pytest(Harness):
             f'--junit-xml={self.report_file}',
             f'--platform={self.instance.platform.name}'
         ]
+
         command.extend([os.path.normpath(os.path.join(
             self.source_dir, os.path.expanduser(os.path.expandvars(src)))) for src in pytest_root])
 
@@ -627,6 +628,19 @@ class Pytest(Harness):
             self.status = TwisterStatus.SKIP
             self.instance.reason = 'No tests collected'
 
+class Shell(Pytest):
+    def generate_command(self):
+        config = self.instance.testsuite.harness_config
+        pytest_root = [os.path.join(ZEPHYR_BASE, 'scripts', 'pylib', 'shell-twister-harness')]
+        config['pytest_root'] = pytest_root
+
+        command = super().generate_command()
+        if config.get('shell_params_file'):
+            p_file = os.path.join(self.source_dir, config.get('shell_params_file'))
+            command.append(f'--testdata={p_file}')
+        else:
+            command.append(f'--testdata={os.path.join(self.source_dir, "test_shell.yml")}')
+        return command
 
 class Gtest(Harness):
     ANSI_ESCAPE = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')

scripts/pylib/twister/twisterlib/testinstance.py

@@ -218,7 +218,16 @@ class TestInstance:
     def testsuite_runnable(testsuite, fixtures):
         can_run = False
         # console harness allows us to run the test and capture data.
-        if testsuite.harness in ['console', 'ztest', 'pytest', 'test', 'gtest', 'robot', 'ctest']:
+        if testsuite.harness in [
+            'console',
+            'ztest',
+            'pytest',
+            'test',
+            'gtest',
+            'robot',
+            'ctest',
+            'shell'
+            ]:
             can_run = True
             # if we have a fixture that is also being supplied on the
             # command-line, then we need to run the test, not just build it.
@@ -304,7 +313,7 @@ class TestInstance:
                             device_testing)
 
         # check if test is runnable in pytest
-        if self.testsuite.harness == 'pytest':
+        if self.testsuite.harness in ['pytest', 'shell']:
             target_ready = bool(
                 filter == 'runnable' or simulator and simulator.name in SUPPORTED_SIMS_IN_PYTEST
             )

scripts/schemas/twister/testsuite-schema.yaml

@@ -107,6 +107,9 @@ schema;scenario-schema:
       type: map
       required: false
       mapping:
+        "shell_params_file":
+          type: str
+          required: false
         "type":
           type: str
           required: false

scripts/tests/twister/pytest_integration/test_harness_pytest.py

@@ -18,6 +18,7 @@ from twisterlib.platform import Platform
 def testinstance() -> TestInstance:
     testsuite = TestSuite('.', 'samples/hello', 'unit.test')
     testsuite.harness_config = {}
+    testsuite.harness = 'pytest'
     testsuite.ignore_faults = False
     testsuite.sysbuild = False
     platform = Platform()