Skip to content

Latest commit

 

History

History
174 lines (84 loc) · 7.16 KB

unit-test-for-girder-plugin-how-to-setup-database-correctly.md

File metadata and controls

174 lines (84 loc) · 7.16 KB
Raw

Unit test for Girder plugin: How to setup database correctly?

Charles on 2019-07-29T16:58:48.044Z

I am creating unit tests for a girder plugin, using a structure similar to the one used in the dicom_viewer, but I have a problem with the setUp function. To make it short, I have girder exception: An assetstore with that name already exists if the setUp function is called more than once.

To go further into the details, I have notice that during the setUp function, my table girder_test_plugin (coming from the girder config) is not really dropped but replaced by another table girder_test_[a long hash]. The name of this table is the “default database name” of the mongo client object: _modelSingletons[0].database contains the bad name.

I have no idea where this name comes from as this is not the one in my girder.cfg file and I do not observe this behavior in other girder plugins like the dicom_viewer. Does someone know where does this bad name comes from and how can I change it ?

Best,

Charles

danlamanna on 2019-07-30T14:46:40.723Z

I am creating unit tests for a girder plugin, using a structure similar to the one used in the dicom_viewer , but I have a problem with the setUp function.

So you’re using cmake and unittest instead of pytest?

To make it short, I have girder exception: An assetstore with that name already exists if the setUp function is called more than once.

This sounds right, setUp isn’t meant to be called more than once. In fact, I don’t think setUp is supposed to be invoked by the caller - the unittest module takes care of calling it for you.

To go further into the details, I have notice that during the setUp function, my table girder_test_plugin (coming from the girder config) is not really dropped but replaced by another table girder_test_[a long hash] .

I’m a bit confused here because the hash is created by pytest. However, pytest tests don’t have a setUp function, they use fixtures for setup and teardown.

For background on the hashing: the pytest runner sets up a database for each test function, and the old runner (unittest/cmake) set up a database per module. Since test function names can be long (test_my_function_does_this_correctly) and Mongo doesn’t allow extremely long database names, we hash the function name to truncate it in a way that provides uniqueness.

The cookiecutter plugin really is the best reference here. It doesn’t include a test that accesses the database, but that’s as simple as writing a regular pytest test that has a db fixture in the argument list. In fact, once pytest is installed you can view the fixtures provided by pytest-girder by running pytest --fixtures:

----------------- fixtures defined from pytest_girder.fixtures -----------------
smtp -- pytest_girder/pytest_girder/fixtures.py:137
    Provides a mock SMTP server for testing.
admin -- pytest_girder/pytest_girder/fixtures.py:161
    Require an admin user.
    
    Provides a user with the admin flag set to True.
user -- pytest_girder/pytest_girder/fixtures.py:175
    Require a user.
    
    Provides a regular user with no additional privileges. Note this fixture requires
    the admin fixture since an administrative user must exist before a regular user can.
fsAssetstore -- pytest_girder/pytest_girder/fixtures.py:190
    Require a filesystem assetstore. Its location will be derived from the test function name.
bcrypt -- pytest_girder/pytest_girder/fixtures.py:21
    Mock out bcrypt password hashing to avoid unnecessary testing bottlenecks.
db -- pytest_girder/pytest_girder/fixtures.py:31
    Require a Mongo test database.
    
    Provides a Mongo test database named after the requesting test function. Mongo databases are
    created/destroyed based on the URI provided with the --mongo-uri option and tear-down
    behavior is modified by the --keep-db option.
server -- pytest_girder/pytest_girder/fixtures.py:79
    Require a CherryPy embedded server.
    
    Provides a started CherryPy embedded server with a request method for performing
    local requests against it. Note: this fixture requires the db fixture.

Charles on 2019-07-30T15:19:47.943Z

So you’re using cmake and unittest instead of pytest?

No, I want to use pytest. And calling pytest on this plugin seems to work. However, the from tests import base seems to import unittest… so I am bit lost here.

This sounds right, setUp isn’t meant to be called more than once. In fact, I don’t think setUp is supposed to be invoked by the caller - the unittest module takes care of calling it for you.

I don’t call it manually, but it is called by my tests environment automatically prior to each call of my test_ functions.

I’m a bit confused here because the hash is created by pytest. However, pytest tests don’t have a setUp function, they use fixtures for setup and teardown.

Thanks for the clarification about the hash, it may explain why I have this behavior and the plugin_viewer doesn’t.

I think I might have a bad cocktail of test environments mixing up together…

I need to fully use the pytest version and not the old unittest one.

I will remove the setUp function and the from tests import base a try to use the db fixture.

Thanks for your help.

danlamanna on 2019-07-30T15:26:05.875Z

I think I might have a bad cocktail of test environments mixing up together…

I need to fully use the pytest version and not the old unittest one.

I will remove the setUp function and the from tests import base a try to use the db fixture.

Sounds good! I slightly misspoke earlier, since the cookiecutter test uses the server fixture and that depends on the db fixture, the database is being used there. For proof, this is the output of pytest --setup-plan when run on the cookiecutter generated plugin:

test/test_load.py::test_import 
SETUP    S fastCrypt
        SETUP    F db
        SETUP    F server (fixtures used: db)
        test/test_load.py::test_import (fixtures used: db, fastCrypt, server)
        TEARDOWN F server
        TEARDOWN F db
TEARDOWN S fastCryptCoverage.py warning: No data was collected. (no-data-collected)

Charles on 2019-07-30T15:53:00.204Z

Thank you for your help, I am reaching a much better solution !

I have a last question:

danlamanna:

For background on the hashing: the pytest runner sets up a database for each test function, and the old runner (unittest/cmake) set up a database per module .

Is it possible to setup a database per module instead of per function ? I have to upload some stuff and then to test the requests and setting up the database each time would take too much time.

Charles on 2019-07-30T15:54:51.507Z

I found out ! I just have to remove the server fixture.

Thanks again for your help !