Writing tests with pytest¶

Pokie includes a set of plugins to aid unit testing of applications with pytest, including a CLI runner. These plugins provide Pokie-related fixtures and, optionally, automatic database management.

To use the pytest integration, it is required to use the application factory to initialize the application, see the tutorial for more details.

Currently, only PostgreSQL is supported for database operations; the configured database user must have database creation/drop privileges; The plugins also assume the user can connect to the database 'postgres', as it is used as the default db for administrative operations.

Note: To use Pokie's unit testing capabilities, you need to install pytest

Pokie Configuration¶

There are several test-related configuration parameters available to control execution of tests, exposed via pokie.config.TestConfigTemplate:

Parameter	Description
TEST_DB_NAME	PostgreSQL test database name
TEST_DB_HOST	PostgreSQL host
TEST_DB_PORT	PostgreSQL port
TEST_DB_USER	PostgreSQL user
TEST_DB_PASSWORD	PostgreSQL password
TEST_DB_SSL	if True, enforces SSL
TEST_MANAGE_DB	if False, no db is managed via pytest-pokie
TEST_SHARE_CTX	if False, create a new application instance between tests (default)
TEST_DB_REUSE	if False, drops and recreates the database between tests (default)
TEST_SKIP_MIGRATIONS	if False, runs migrations when creating the database
TEST_SKIP_FIXTURES	if False, runs fixtures when creating the database

Application lifecycle parameters¶

TEST_SHARE_CTX

False (default): Each test is run with a separate application instance; the application is bootstrapped at each test, by using the existing application factory.

True: All tests are run with the same pokie FlaskApplication and Flask instance; services, events, etc. will be managed and cached as in a production run.

Database management¶

Please note: The credentials provided to the test database must have enough privileges for the required operations, such as creating and dropping databases.

TEST_MANAGE_DB

False (default): If TEST_MANAGE_DB is False, database management is completely ignored, and available db connection is the regular application connection. All database test configurations are ignored. With this mode, it is up to the developer to ensure a clean state between database runs.

True: If TEST_MANAGE_DB is True, pytest-pokie will manage the database connection using the available test credentials. The global database connection is replaced with the test connection, and fixtures and migrations may be executed between tests.

TEST_DB_REUSE

False (default): if TEST_DB_REUSE is False, pytest-pokie will attempt to drop and recreate the test database between each test.

True: if TEST_DB_REUSE is True, pytest-pokie will not drop the testing database if exists. If it doesn't exist, it will attempt to create the database and optionally run migrations and fixtures, depending on TEST_SKIP_MIGRATIONS and TEST_SKIP_FIXTURES values.

TEST_SKIP_MIGRATIONS

False (default): Existing SQL migrations will be run when the database is recreated.

True: Existing SQL migrations are ingored, even if the database is recreated.

TEST_SKIP_FIXTURES

False (default):Existing fixtures will be run when the database is recreated.

True: Existing fixtures are ignored, even if the database is recreated.

Available fixtures¶

Note: fixtures depend on the predefined values for the different DI constants as specified on the pokie.constants file.

Fixture	Description
pokie_app	Pokie Flask object
pokie_config	Pokie Config object
pokie_di	Pokie Di object
pokie_db	Pokie Database client
pokie_client	Flask test client

Writing Tests¶

Pytest must be invoked using the internal Pokie pytest runner. The pytest runner will automatically add the required dependencies to pytest. All additional pytest command-line arguments can be specified:

$ python main.py pytest --help

[Pokie] Running pytest with: ['--help']
usage: main.py [options] [file_or_dir] [file_or_dir] [...]

positional arguments:
  file_or_dir

general:
  -k EXPRESSION         only run tests which match the given substring expression. An expression is a python evaluatable expression where all names are substring-matched against test names and their parent classes. Example: -k
                        'test_method or test_other' matches all test functions and classes whose name contains 'test_method' or 'test_other', while -k 'not test_method' matches those that don't contain 'test_method' in their names. -k
                        'not test_method and not test_other' will eliminate the matches. Additionally keywords are matched to classes and functions containing extra names in their 'extra_keyword_matches' set, as well as functions which
                        have names assigned directly to them. The matching is case-insensitive.
  -m MARKEXPR           only run tests matching given mark expression.
                        For example: -m 'mark1 and not mark2'.
  --markers             show markers (builtin, plugin and per-project ones).
  -x, --exitfirst       exit instantly on first error or failed test.
  --fixtures, --funcargs
(...)
$

The scaffold structure is similar to the common pytest usage:

some_module/
  (...)
main.py
tests/
  __init__.py
  some_module/
    __init__.py
    test_something.py

test_something.py:

def test_example_1(pokie_app, pokie_di):
    assert pokie_app is not None
    assert pokie_app.di == pokie_di


def test_example_2(pokie_db, pokie_service_manager):
    assert pokie_db is not None
    assert pokie_service_manager is not None

And to run the tests:

$ python3 main.py pytest

Using tox¶

Example tox.ini:

[tox]
envlist =
    py39
    py310

[testenv]
deps = -rrequirements-dev.txt
commands = python3 main.py pytest

Example requirements-dev.txt:

pytest==7.3.1
pokie==1.0.0
tox==4.5.1

Running tox:

$ tox -e py310