nixos/test-driver: use RequestedAssertionFailed/TestScriptError in Machine class

I think it's reasonable to also have this kind of visual distinction
here between test failures and actual errors from the test framework.

A failing `machine.require_unit_state` now lookgs like this for
instance:

    !!! Traceback (most recent call last):
    !!!   File "<string>", line 3, in <module>
    !!!     machine.require_unit_state("postgresql","active")
    !!!
    !!! RequestedAssertionFailed: Expected unit 'postgresql' to to be in state 'active' but it is in state 'inactive'

Co-authored-by: Benoit de Chezelles <bew@users.noreply.github.com>
This commit is contained in:
Maximilian Bosch 2025-03-18 11:02:47 +00:00
parent a1dfaf51e2
commit 11ff96a679
No known key found for this signature in database
4 changed files with 62 additions and 28 deletions

View file

@ -21,7 +21,7 @@ target-version = "py312"
line-length = 88
lint.select = ["E", "F", "I", "U", "N"]
lint.ignore = ["E501"]
lint.ignore = ["E501", "N818"]
# xxx: we can import https://pypi.org/project/types-colorama/ here
[[tool.mypy.overrides]]

View file

@ -11,6 +11,7 @@ from pathlib import Path
from typing import Any
from unittest import TestCase
from test_driver.errors import RequestedAssertionFailed, TestScriptError
from test_driver.logger import AbstractLogger
from test_driver.machine import Machine, NixStartScript, retry
from test_driver.polling_condition import PollingCondition
@ -19,6 +20,18 @@ from test_driver.vlan import VLan
SENTINEL = object()
class AssertionTester(TestCase):
"""
Subclass of `unittest.TestCase` which is used in the
`testScript` to perform assertions.
It throws a custom exception whose parent class
gets special treatment in the logs.
"""
failureException = RequestedAssertionFailed
def get_tmp_dir() -> Path:
"""Returns a temporary directory that is defined by TMPDIR, TEMP, TMP or CWD
Raises an exception in case the retrieved temporary directory is not writeable
@ -41,14 +54,6 @@ def pythonize_name(name: str) -> str:
return re.sub(r"^[^A-z_]|[^A-z0-9_]", "_", name)
class NixOSAssertionError(AssertionError):
pass
class Tester(TestCase):
failureException = NixOSAssertionError
class Driver:
"""A handle to the driver that sets up the environment
and runs the tests"""
@ -126,7 +131,7 @@ class Driver:
try:
yield
except Exception as e:
self.logger.error(f'Test "{name}" failed with error: "{e}"')
self.logger.log_test_error(f'Test "{name}" failed with error: "{e}"')
raise e
def test_symbols(self) -> dict[str, Any]:
@ -151,7 +156,7 @@ class Driver:
serial_stdout_on=self.serial_stdout_on,
polling_condition=self.polling_condition,
Machine=Machine, # for typing
t=Tester(),
t=AssertionTester(),
)
machine_symbols = {pythonize_name(m.name): m for m in self.machines}
# If there's exactly one machine, make it available under the name
@ -177,7 +182,7 @@ class Driver:
symbols = self.test_symbols() # call eagerly
try:
exec(self.tests, symbols, None)
except NixOSAssertionError:
except TestScriptError:
exc_type, exc, tb = sys.exc_info()
filtered = [
frame
@ -186,13 +191,12 @@ class Driver:
]
self.logger.log_test_error("Traceback (most recent call last):")
code = self.tests.splitlines()
for frame, line in zip(filtered, traceback.format_list(filtered)):
self.logger.log_test_error(line.rstrip())
if lineno := frame.lineno:
self.logger.log_test_error(
f" {code[lineno - 1].strip()}",
)
self.logger.log_test_error(f" {code[lineno - 1].strip()}")
self.logger.log_test_error("") # blank line for readability
exc_prefix = exc_type.__name__ if exc_type is not None else "Error"

View file

@ -0,0 +1,23 @@
class TestScriptError(Exception):
"""
The base error class to indicate that the test script failed.
This (and its subclasses) get special treatment, i.e. only stack
frames from `testScript` are printed and the error gets prefixed
with `!!!` to make it easier to spot between other log-lines.
This class is used for errors that aren't an actual test failure,
but also not a bug in the driver, e.g. failing OCR.
"""
class RequestedAssertionFailed(TestScriptError):
"""
Subclass of `TestScriptError` that gets special treatment.
Exception raised when a requested assertion fails,
e.g. `machine.succeed(...)` or `t.assertEqual(...)`.
This is separate from the base error class, to have a dedicated class name
that better represents this kind of failures.
(better readability in test output)
"""

View file

@ -18,6 +18,7 @@ from pathlib import Path
from queue import Queue
from typing import Any
from test_driver.errors import RequestedAssertionFailed, TestScriptError
from test_driver.logger import AbstractLogger
from .qmp import QMPSession
@ -128,7 +129,7 @@ def _preprocess_screenshot(screenshot_path: str, negate: bool = False) -> str:
)
if ret.returncode != 0:
raise Exception(
raise TestScriptError(
f"Image processing failed with exit code {ret.returncode}, stdout: {ret.stdout.decode()}, stderr: {ret.stderr.decode()}"
)
@ -139,7 +140,7 @@ def _perform_ocr_on_screenshot(
screenshot_path: str, model_ids: Iterable[int]
) -> list[str]:
if shutil.which("tesseract") is None:
raise Exception("OCR requested but enableOCR is false")
raise TestScriptError("OCR requested but enableOCR is false")
processed_image = _preprocess_screenshot(screenshot_path, negate=False)
processed_negative = _preprocess_screenshot(screenshot_path, negate=True)
@ -162,7 +163,7 @@ def _perform_ocr_on_screenshot(
capture_output=True,
)
if ret.returncode != 0:
raise Exception(f"OCR failed with exit code {ret.returncode}")
raise TestScriptError(f"OCR failed with exit code {ret.returncode}")
model_results.append(ret.stdout.decode("utf-8"))
return model_results
@ -179,7 +180,9 @@ def retry(fn: Callable, timeout: int = 900) -> None:
time.sleep(1)
if not fn(True):
raise Exception(f"action timed out after {timeout} seconds")
raise RequestedAssertionFailed(
f"action timed out after {timeout} tries with one-second pause in-between"
)
class StartCommand:
@ -402,14 +405,14 @@ class Machine:
def check_active(_last_try: bool) -> bool:
state = self.get_unit_property(unit, "ActiveState", user)
if state == "failed":
raise Exception(f'unit "{unit}" reached state "{state}"')
raise RequestedAssertionFailed(f'unit "{unit}" reached state "{state}"')
if state == "inactive":
status, jobs = self.systemctl("list-jobs --full 2>&1", user)
if "No jobs" in jobs:
info = self.get_unit_info(unit, user)
if info["ActiveState"] == state:
raise Exception(
raise RequestedAssertionFailed(
f'unit "{unit}" is inactive and there are no pending jobs'
)
@ -424,7 +427,7 @@ class Machine:
def get_unit_info(self, unit: str, user: str | None = None) -> dict[str, str]:
status, lines = self.systemctl(f'--no-pager show "{unit}"', user)
if status != 0:
raise Exception(
raise RequestedAssertionFailed(
f'retrieving systemctl info for unit "{unit}"'
+ ("" if user is None else f' under user "{user}"')
+ f" failed with exit code {status}"
@ -454,7 +457,7 @@ class Machine:
user,
)
if status != 0:
raise Exception(
raise RequestedAssertionFailed(
f'retrieving systemctl property "{property}" for unit "{unit}"'
+ ("" if user is None else f' under user "{user}"')
+ f" failed with exit code {status}"
@ -502,7 +505,7 @@ class Machine:
info = self.get_unit_info(unit)
state = info["ActiveState"]
if state != require_state:
raise Exception(
raise RequestedAssertionFailed(
f"Expected unit '{unit}' to to be in state "
f"'{require_state}' but it is in state '{state}'"
)
@ -656,7 +659,9 @@ class Machine:
(status, out) = self.execute(command, timeout=timeout)
if status != 0:
self.log(f"output: {out}")
raise Exception(f"command `{command}` failed (exit code {status})")
raise RequestedAssertionFailed(
f"command `{command}` failed (exit code {status})"
)
output += out
return output
@ -670,7 +675,9 @@ class Machine:
with self.nested(f"must fail: {command}"):
(status, out) = self.execute(command, timeout=timeout)
if status == 0:
raise Exception(f"command `{command}` unexpectedly succeeded")
raise RequestedAssertionFailed(
f"command `{command}` unexpectedly succeeded"
)
output += out
return output
@ -915,7 +922,7 @@ class Machine:
ret = subprocess.run(f"pnmtopng '{tmp}' > '{filename}'", shell=True)
os.unlink(tmp)
if ret.returncode != 0:
raise Exception("Cannot convert screenshot")
raise TestScriptError("Cannot convert screenshot")
def copy_from_host_via_shell(self, source: str, target: str) -> None:
"""Copy a file from the host into the guest by piping it over the