Pytest-eliot
Fixtures to use eliot from pytest.
Testing your logging
pytest-eliot allows using eliot with pytest. The usage is kind of different and adapted to pytest style.
https://eliot.readthedocs.io/en/stable/generating/testing.html
Linting your logs
pytest-eliot provides a fixture that can be used as a context manager. The eliot capture_logging is provided as the fixture eliot_capture_logging.
The context manager will ensure that:
- You haven't logged anything that isn't JSON serializable.
- There are no unexpected tracebacks, indicating a bug somewhere in your code.
def test_mytest(eliot_capture_logging):
with eliot_capture_logging():
call_my_function()Making assertions about the logs
You can also ensure the correct messages were logged.
from eliot import log_message
class UserRegistration(object):
def __init__(self):
self.db = {}
def register(self, username, password, age):
self.db[username] = (password, age)
log_message(message_type="user_registration",
username=username, password=password,
age=age)Here's how we'd test it:
from myapp.registration import UserRegistration
def test_registration(eliot_capture_logging):
registry = UserRegistration()
with eliot_capture_logging() as logger:
registry.register("john", "password", 12)
msg = logger.messages[0]
fields = {"username": "john",
"password": "password",
"age": 12}
assert fields.items() <= msg.items() # Fields items is a subset of msg items.
assert registry.db["john"] == ("password", 12)Testing tracebakcs
Eliot provides utilities for making assertions about the structure of individual messages and actions. The simplest method is using the assertHasMessage utility function which asserts that a message of a given message type has the given fields:
def test_badpath(eliot_capture_logging):
mything = MyThing()
with eliot_capture_logging() as logger:
mything.load("/nonexistant/path")
messages = logger.flush_tracebacks(OSError)
assert len(messages) == 1Testing Message and Action Structure
pytest-eliot provides utilities for making assertions about the structure of
individual messages and actions. The simplest method is using the
eliot_has_message utility function which asserts that a message of a given
message type has the given fields:
def test_registration(eliot_capture_logging, eliot_has_message):
with eliot_capture_logging() as logger:
registry = UserRegistration()
registry.register("john", "password", 12)
assert eliot_has_message(
logger, message_type="user_registration",
fields={
"username": "john",
"password:" "password",
"age": 12
}
)Custom JSON encoding
Custom testing setup
Must wrap all low level functions here as fixtures.
