Description
I have a command line command that I'm trying to write an end-to-end test for to make sure everything is working well. I wanted to invoke the CLI via a multiprocessing.Process, because when the CLI starts running it configures the root logger, and I want to test that, along with everything else, without creating inconsistencies in my test suite. Below is a simple of the type of test I'm interested in doing. You can see that I have child, which is the entrypoint of my CLI, you can see that it configures logging, and also that it makes a couple of print statements. The test itself verifies both the print statement and the log message show up in stdout, which is redirected to a file in a child process.
When I run this test with unittests, everything passes. When I run with nose2, I get a failure. See below for details.
tests/test_example.py
import logging
import sys
import tempfile
import unittest
from pathlib import Path
from multiprocessing import Process
def child():
logging.basicConfig(
handlers=[logging.StreamHandler(sys.stdout)],
level=logging.INFO,
format="%(message)s",
datefmt="%Y-%m-%dT%H:%M:%S%z",
)
print("MY PRINT STATEMENT")
logging.info("MY LOG MESSAGE")
def child_wrapper(target, stdout_file, stderr_file):
sys.stdout = stdout_file.open("w")
sys.stderr = stderr_file.open("w")
try:
target()
finally:
sys.stdout.flush()
sys.stderr.flush()
class TestLoggingInChildProc(unittest.TestCase):
def test_logging_in_child_proc(self):
with tempfile.TemporaryDirectory() as d:
stdout_file = Path(f"{d}/stdout.txt")
stderr_file = Path(f"{d}/stderr.txt")
p = Process(
target=child_wrapper,
args=[child, stdout_file, stderr_file],
)
p.start()
p.join()
p.close()
self.assertEqual(
"MY PRINT STATEMENT\nMY LOG MESSAGE",
stdout_file.read_text().strip()
)
self.assertEqual("", stderr_file.read_text().strip())
When I run tree ., I see:
.
└── tests
├── __init__.py
└── test_example.py
1 directory, 2 files
When I run python -m unittest tests.test_example the test passes, but when I run nose2 test_example the test fails. Here is the failure text:
F
======================================================================
FAIL: test_logging_in_child_proc (tests.test_example.TestLoggingInChildProc)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/tmp/tests/test_example.py", line 47, in test_logging_in_child_proc
self.assertEqual(
AssertionError: 'MY PRINT STATEMENT\nMY LOG MESSAGE' != 'MY PRINT STATEMENT'
- MY PRINT STATEMENT
? -
+ MY PRINT STATEMENT- MY LOG MESSAGE
----------------------------------------------------------------------
Ran 1 test in 0.004s
FAILED (failures=1)
When I invoke this test using python -m unittest test_example.py the test passes. However, when I invoke this script using nose2