pytest: gdbstub: Add GDB helper to Twister pytest plugin

Add GDB helper and fixture to Twister pytest plugin to reuse
it for test cases where GDB execution is needed.

Adjust GDB stub test to use the new helper class.

Signed-off-by: Dmitrii Golovanov <dmitrii.golovanov@intel.com>

scripts/pylib/pytest-twister-harness/src/twister_harness/fixtures.py

@@ -3,7 +3,8 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import logging
-from typing import Generator, Type
+from subprocess import CompletedProcess
+from typing import Generator, Type, Callable
 
 import pytest
 
@@ -12,6 +13,7 @@
 from twister_harness.twister_harness_config import DeviceConfig, TwisterHarnessConfig
 from twister_harness.helpers.shell import Shell
 from twister_harness.helpers.mcumgr import MCUmgr
+from twister_harness.helpers.gdb import GDBrunner
 
 logger = logging.getLogger(__name__)
 
@@ -66,3 +68,14 @@ def is_mcumgr_available() -> None:
 @pytest.fixture()
 def mcumgr(is_mcumgr_available: None, dut: DeviceAdapter) -> Generator[MCUmgr, None, None]:
     yield MCUmgr.create_for_serial(dut.device_config.serial)
+
+
+@pytest.fixture(scope='function')
+def gdb_batch_make(dut: DeviceAdapter) -> Callable[[DeviceAdapter, str, str, float], CompletedProcess]:
+    """Returns GDBrunner factory method to call in a test context"""
+    def batch_make(dut: DeviceAdapter, gdb_target_remote: str, gdb_script: str, gdb_timeout: float) -> CompletedProcess:
+      gdb = GDBrunner(dut)
+      return gdb.run_script(gdb_target_remote, gdb_script, gdb_timeout)
+    #
+    return batch_make
+#

scripts/pylib/pytest-twister-harness/src/twister_harness/helpers/gdb.py

@@ -0,0 +1,64 @@
+# Copyright (c) 2023 Intel Corporation.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import os
+import subprocess
+import sys
+import logging
+import shlex
+
+from twister_harness.device.device_adapter import DeviceAdapter
+
+ZEPHYR_BASE = os.getenv("ZEPHYR_BASE")
+sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts", "pylib", "twister"))
+from twisterlib.cmakecache import CMakeCache
+
+logger = logging.getLogger(__name__)
+
+
+class GDBrunner:
+    """
+    Helper class to run GDB process as a part of the test.
+    """
+
+    def __init__(self, device: DeviceAdapter) -> None:
+        build_dir = device.device_config.build_dir
+        cmake_cache = CMakeCache.from_file(os.path.join(build_dir, 'CMakeCache.txt'))
+
+        gdb_exec = cmake_cache.get('CMAKE_GDB', None)
+        assert gdb_exec
+
+        self.source_dir = cmake_cache.get('APPLICATION_SOURCE_DIR', None)
+        assert self.source_dir
+
+        self.build_image = cmake_cache.get('BYPRODUCT_KERNEL_ELF_NAME', None)
+        assert self.build_image
+
+        gdb_log_file = os.path.join(build_dir, 'gdb.log')
+
+        self.command = [gdb_exec, '-batch',
+           '-ex', f'set pagination off',
+           '-ex', f'set trace-commands on',
+           '-ex', f'set logging file {gdb_log_file}',
+           '-ex', f'set logging enabled on'
+        ]
+    #
+
+    def run_script(self, target_remote: str, gdb_script:str, timeout:float | None = None) -> subprocess.CompletedProcess:
+        """
+        Run GDB process which executes a script connecting to remote target backend.
+        """
+        cmd = self.command + [
+           '-ex', f'target remote {target_remote}',
+           '-x', f'{self.source_dir}/{gdb_script}',
+           self.build_image
+        ]
+        logger.info(f'Run GDB: {shlex.join(cmd)}')
+        result = subprocess.run(cmd, capture_output=True, text=True, timeout=timeout)
+        logger.info(f'GDB ends rc={result.returncode}')
+        return result
+
+# GDBrunner

tests/subsys/debug/gdbstub/pytest/conftest.py

@@ -17,7 +17,7 @@ def gdb_script(request):
 
 @pytest.fixture()
 def gdb_timeout(request):
-    return int(request.config.getoption('--gdb_timeout', default=60))
+    return float(request.config.getoption('--gdb_timeout', default=60))
 
 @pytest.fixture()
 def gdb_target_remote(request):

tests/subsys/debug/gdbstub/pytest/test_gdbstub.py

@@ -2,45 +2,14 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-import os
-import subprocess
-import sys
+from subprocess import CompletedProcess
 import logging
-import shlex
 import re
 import pytest
 from twister_harness import DeviceAdapter
 
-ZEPHYR_BASE = os.getenv("ZEPHYR_BASE")
-sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts", "pylib", "twister"))
-from twisterlib.cmakecache import CMakeCache
-
 logger = logging.getLogger(__name__)
 
-@pytest.fixture()
-def gdb_process(dut: DeviceAdapter, gdb_script, gdb_timeout, gdb_target_remote):
-    build_dir = dut.device_config.build_dir
-    cmake_cache = CMakeCache.from_file(os.path.join(build_dir, 'CMakeCache.txt'))
-    gdb_exec = cmake_cache.get('CMAKE_GDB', None)
-    assert gdb_exec
-    source_dir = cmake_cache.get('APPLICATION_SOURCE_DIR', None)
-    assert source_dir
-    build_image = cmake_cache.get('BYPRODUCT_KERNEL_ELF_NAME', None)
-    assert build_image
-    gdb_log_file = os.path.join(build_dir, 'gdb.log')
-    cmd = [gdb_exec, '-batch',
-           '-ex', f'set pagination off',
-           '-ex', f'set trace-commands on',
-           '-ex', f'set logging file {gdb_log_file}',
-           '-ex', f'set logging enabled on',
-           '-ex', f'target remote {gdb_target_remote}',
-           '-x', f'{source_dir}/{gdb_script}', build_image]
-    logger.info(f'Run GDB: {shlex.join(cmd)}')
-    result = subprocess.run(cmd, capture_output=True, text=True, timeout=gdb_timeout)
-    logger.info(f'GDB ends rc={result.returncode}')
-    return result
-#
-
 @pytest.fixture(scope="module")
 def expected_app():
     return [
@@ -66,17 +35,21 @@ def expected_gdb_detach():
     re.compile(r'Inferior.*detached')  # QEMU gdbstub
     ]
 
+@pytest.fixture(scope='function')
+def gdb_batch(dut: DeviceAdapter, gdb_batch_make, gdb_target_remote, gdb_script, gdb_timeout) -> CompletedProcess:
+    return gdb_batch_make(dut, gdb_target_remote, gdb_script, gdb_timeout)
+
 
-def test_gdbstub(dut: DeviceAdapter, gdb_process, expected_app, expected_gdb, expected_gdb_detach):
+def test_gdbstub(dut: DeviceAdapter, gdb_batch: CompletedProcess, expected_app, expected_gdb, expected_gdb_detach):
     """
     Test gdbstub feature using a GDB script. We connect to the DUT, run the
     GDB script then evaluate return code and expected patterns at the GDB
     and Test Applicaiton outputs.
     """
-    logger.debug(f"GDB output:\n{gdb_process.stdout}\n")
-    assert gdb_process.returncode == 0
-    assert all([ex_re.search(gdb_process.stdout, re.MULTILINE) for ex_re in expected_gdb]), 'No expected GDB output'
-    assert any([ex_re.search(gdb_process.stdout, re.MULTILINE) for ex_re in expected_gdb_detach]), 'No expected GDB quit'
+    logger.debug(f"GDB output:\n{gdb_batch.stdout}\n")
+    assert gdb_batch.returncode == 0
+    assert all([ex_re.search(gdb_batch.stdout, re.MULTILINE) for ex_re in expected_gdb]), 'No expected GDB output'
+    assert any([ex_re.search(gdb_batch.stdout, re.MULTILINE) for ex_re in expected_gdb_detach]), 'No expected GDB quit'
     app_output = '\n'.join(dut.readlines(print_output = False))
     logger.debug(f"App output:\n{app_output}\n")
     assert all([ex_re.search(app_output, re.MULTILINE) for ex_re in expected_app]), 'No expected Application output'