Plugin features#

Fixtures#

pytest introduces fixtures to simplify testing and share common resources between tests. More about fixtures is in official pytest documentation as well as see the list of fixtures provided by pytest package itself.

Location fixtures#

Fixtures that helps to get directories

Name

Description

cur_dir

gets the absolute path to the folder with the test.

par_dir

gets the absolute path to the parent folder of the test.

keep_generated_dir

returns the absolute path to the folder were the test will be saved if the keep-generated flag is specified.

Session fixtures#

Session fixtures provide an instance of otp.Session to a test and take care of gracefully destroying after.

Name

Description

f_session

The function scope session. A session instance is created before a test and destroyed after.

Example:

def test_1(f_session):
    # `f_session` points to a new instance of the otp.Session
    ...

def test_2(f_session):
    # here `f_session` is a new instance
    ...

c_session

The class scope session.

Example:

class TestSomething:

    def test_1(self, c_session):
        # `c_session` is created for this class on the first occurance
        ...

    def test_2(self, c_session):
        # the `c_session` instance is the same as in test `test_1`


class TestSomethingElse:

    def test_1(self, c_session):
        # here the `c_session` is a new instance because it is a test
        # of another test class
        ...

The f_session fixture in classes creates a new instance for every test.

m_session

The module scope session; it is created on the first usage and destroyed only when all tests in the test file are executed.

otq_path

Allows to specify OTQ_PATH in ontick config with the location of OTQ files. By default OTQ_PATH is not specified for session fixtures.

You need to override this fixture to specify your own value.

import pytest


@pytest.fixture
def otq_path(cur_dir):
    return cur_dir / 'otqs'


def test_1(f_session):
    # an instance of that `f_session` will search for otqs in
    # specified path
    ...

def test_2(f_session):
    # the same with this instance of the `f_session`
    ...

Note

The otq_path fixture will be automatically applied for all tests with the same scope. Scope visibility could be adjusted using modules and classes. For example

class TestCustomOTQS:

    @pytest.fixture
    def otq_path(self, cur_dir):
        # this fixture will be used by any session fixtrue
        # in this class
        ...


def test_1(f_session):
    # ... but makes not effect on this session

Default values fixtures#

Name

Description

Expected type

Default

default_tz

Allows to override the default timezone.

str

EST5EDT

default_start_time

Start time for any query interval of the otp.run

str

2003/12/01 00:00:00

default_end_time

End time for any query interval of the otp.run

str

2003/12/04 00:00:00

default_symbol

Default symbol name that is used everywhere where OneTick requires it, for example any tick source like the otp.Source

str

AAPL

default_database

Default database that is used everywhere where OneTick expects it

str

DEMO_L1

These fixtures are automatically picked up by the provided session fixtures such as f_session. You just need to override a fixture with your value and it will be automatically picked up for all fixtures with the same scope.

For example

@pytest.fixture
def default_tz():
   return 'GMT'

def test_something(f_session):
    # f_session picks up the `default_tz` value on initialization
    ...

Note

Default values come from the default OneTick installation that distributes a sample of trades in the DEMO_L1 database. Using this default values helps share issues with the OneTick support team.

The --keep-generated flag#

The plugin adds a custom --keep-generated flag to pytest that allows to control the lifetime of generated resources during tests: config files for otp.Session, databases, OTQ queries, etc.

It’s helpful in case something goes wrong and a developer wants to take a closer look into the resources generated during testing.

Description from the pytest -h

custom options:
  --keep-generated=KEEP_GENERATED

    Policy to keep temporary generated files, that has several options to run:
    * 'never' - do not keep any temporary generated files during the test run (default)
    * 'fail' - keep temporary generated files only when a test fails
    * 'always' - keep temporary generated files for every test
    Example: pytest --keep-generated=fail

This flag handles only folders and files that are created using the otp.TmpFile and otp.TmpDir correspondingly. We use theses classes to create databases, log files and any configuration files related to the otp.Session.

Developers could also use these classes in code and tests to handle them in case of testing and debugging.

Example:

pytest -vs --keep-generated=always

This command will print out the path to a folder with the saved resources

$ pytest -vs

=========================== test session starts =====================
platform linux -- Python 3.9.6, pytest-7.1.2, pluggy-1.3.0 -- python3

OneTick build: 20230831120000, onetick-py: 1.82.0, onetick-py-test: 1.1.34
cachedir: .pytest_cache
rootdir: /project-folder
plugins: timeout-1.3.3, mock-1.11.0, pyfakefs-5.2.4, cov-2.7.1
collected 1 item

test_simple.py::test_simple
                 Time  BUY_SIZE  BUY_COUNT  SELL_SIZE  SELL_COUNT  FLAG
0 2023-12-01 00:00:01         5          1         27           2    -1
1 2023-12-01 00:00:02       100          1         70           1     1
2 2023-12-01 00:00:03        55          1         59           1     0
PASSED
[[ Generated resources: /tmp/test_user/run_20231129_101141_23129/test_my/test_simple ]]

This [[ Generated resources: /tmp/test_user/run_20231129_101141_23129/test_my/test_simple ]] line points us where we could find the resources. Let’s go there and list the folder

$ cd /tmp/test_user/run_20231129_101141_23129/test_my/test_simple
$ ls

boisterous-ant.locator  dancing-wombat.cfg  green-buffalo.run.otq
run.sh  tunneling-hippo.acl

  • dancing-wombat.cfg is a OneTick config file that the test’s session creates and uses

  • tunneling-hippo.acl is the ACL that the dancing-wombat.cfg config points to

  • boisterous-ant.locator is a locator file that the dancing-wombat.cfg config points to; it consists of databases that have been added into the test’s session

  • green-buffalo.run.otq is a query that has been passed into otp.run during tests; every call of that function dumps a query that can then be viewed as an OTQ

  • the run.sh script allows to spin up a tick server using the saved configs and to play with the saved OTQ queries (On Windows it is the run.bat script)

The --show-stack-trace flag#

Show stack trace with a line of onetick.py code where the issues has happened in case of failure.

This flag enables the same mechanism like the otp.config['show_stack_info'] flag does.

Other#

Our plugin adds OneTick version into the pytest output. You might find it in the header of the output where pytest lists the plugins and their versions.

In the following example

$ pytest -vs

=========================== test session starts =====================
platform linux -- Python 3.9.6, pytest-7.1.2, pluggy-1.3.0 -- python3

OneTick build: 20230831120000, onetick-py: 1.82.0, onetick-py-test: 1.1.34
cachedir: .pytest_cache
...

the following line shows OneTick related dependencies

OneTick build: 20230831120000, onetick-py: 1.82.0, onetick-py-test: 1.1.34