[test] Add shared pytest fixtures via conftest.py

[adity1raut]

Related Issue / Discussion:

Please delete the option which is not relevant.

Fixes Issue #XX
Relates to discussion [Improve Test Framework – GSoC 2025 Code Challenge]

Changes:

• New tests/conftest.py – shared pytest fixtures for the WRT test suite

Further Details:

Summary:

Before: Every test file independently called basic_test_func.create_dummy_Direct_Power_Ship(),
basic_test_func.create_dummy_IsoFuel_object(), and repeated path-building
boilerplate (os.path.dirname(__file__) + joins) to set up the same objects.
This made tests harder to read and changes to test setup require edits in
multiple files.

After: A single tests/conftest.py provides session- and function-scoped
fixtures that any test can request by name. Session-scoped fixtures
(simpleship, manualship, isofuel_algorithm, isobased_algorithm,
wrt_config, ship_config) are constructed once per test run, reducing I/O
overhead. Function-scoped fixtures (base_ship_config_dict,
simpleship_from_dict) are recreated per test to prevent state leakage.

Fixtures added:

Fixture	Scope	Purpose
test_data_dir	session	Absolute path to tests/data/
tests_config_path	session	Path to config.tests.json
wrt_config	session	Config loaded from config.tests.json
ship_config	session	ShipConfig loaded from config.tests.json
simpleship	session	DirectPowerBoat with auto-calculated geometry
manualship	session	DirectPowerBoat with manual geometry
base_ship_config_dict	function	Minimal valid ship config as dict
simpleship_from_dict	function	DirectPowerBoat built from dict
isofuel_algorithm	session	IsoFuel routing algorithm object
isobased_algorithm	session	IsoBased routing algorithm object

Dependencies:

No new dependencies. conftest.py uses only packages already listed in
requirements.test.txt (pytest) and the existing tests/basic_test_func.py
helper module.

Changes:

Please list the central functionalities that have been changed:

• New class / file / …
• Modified class / file / …

Further Details:

Summary:

Please mention the relevant motivation and context of your changes and shortly describe the behaviour before and after your modifications.

Dependencies:

Please list new dependencies that are required for this modification.

PR Checklist:

In the context of this PR, I:

• have (already previously) filled the 52North Contributor License Agreement and received positive feedback on this matter
• have filled the 52North Contributor License Agreement and am waiting for feedback
• provide unit tests embedded in the WRT test framework (WeatherRoutingTool/tests) that allow the simple testing of the new/modified functionalities. All (previous and new) unit tests execute without new error messages.
• ensure that the code formatter runs without errors/warnings
• ensure that my changes follow the WRT’s guidelines for contributing at the time of the contribution

Please consider that PRs which do not meet the requirements specified in the checklist will not be evaluated. Also, PRs with no activities will be closed after a reasonable amount of time.

[kdemmich]

Hi @adity1raut, thank you for your PR. We appreciate the time and effort that was put into it. Please be aware that we require to follow 52 North's CLA guidelines for all PRs and, in particular, fill the 52°North Contributor License Agreement. As long as this has not been filled, I can not assign you to any issues or merge any PRs. Please don't hesitate to contact me in case of related questions.