What do these changes do?

1. Fixes wrong fixtures in tests

=========================== short test summary info ============================
ERROR tests/unit/pact_broker/test_pact_checkout_release.py::test_provider_against_pact - AttributeError: <module 'simcore_service_api_server.services_rpc.wb_api_server' from '/home/runner/work/osparc-simcore/osparc-simcore/.venv/lib/python3.11/site-packages/simcore_service_api_server/services_rpc/wb_api_server.py'> does not have the attribute '_checkout_licensed_item_for_wallet'
============================== 2 errors in 2.65s ===============================

2. Improves skip test mechanism
3. Improves doc

$ make help       

Targets for 'api-server':

reqs                 compiles pip requirements (.in -> .txt)
test-api             Runs schemathesis against development server (NOTE: make up-devel first)
test-pacts           Test pacts. Usage: PACT_BROKER_USERNAME=your_username PACT_BROKER_PASSWORD=your_password PACT_BROKER_URL=your_broker_url make test-pacts

In detail (AI)

This pull request refactors and improves the pact broker test setup for the API server, focusing on clearer test logic, more robust fixture management, and better handling of credentials and dependencies. The changes streamline how dependencies are overridden, improve the handling of missing credentials, and update test naming for clarity.

Test infrastructure improvements:

• Updated the pact_broker_credentials fixture to use pytest.skip instead of pytest.fail when credentials are missing, and clarified its return type. This ensures tests are skipped gracefully if required environment variables or CLI arguments are not provided.
• Changed dependency overrides in the running_test_server_url fixture to use an inline function for mocking identity, and ensured cleanup by removing the override after the test completes. [1] [2]

Test logic and naming:

• Renamed test functions from test_provider_against_pact to more descriptive names (test_osparc_api_server_checkout_release_pact and test_osparc_api_server_licensed_items_pact), and removed unnecessary environment variable checks for test skipping, relying instead on the improved fixture logic. [1] [2]
• Updated comments in test setup to clarify which pact contracts are being verified. [1] [2]

Fixture and import clean-up:

• Improved the way dependencies are mocked in test fixtures for webserver_rpc and resource_usage_tracker, using more robust patching and dependency overrides, and cleaning up imports for clarity and correctness. [1] [2]
• Added missing type annotations and removed unused imports in several test files for better code hygiene. [1] [2] [3] [4]

Documentation updates:

• Improved the README.md instructions for pact broker usage, adding clearer steps for installing and publishing contracts.

Related issue/s

• Follows up first trial in 🎨✅ [Maintenance] Add mock handler factory for LicensesRpcApi to fix pact tests #8455

How to test

cd services/api-server             
(.venv) ➜  api-server git:(fix/pact-tests) ✗ make install-dev
(.venv) ➜  api-server git:(fix/pact-tests) ✗ make help       
Targets for 'api-server':

reqs                 compiles pip requirements (.in -> .txt)
test-api             Runs schemathesis against development server (NOTE: make up-devel first)
test-pacts           Test pacts. Usage: PACT_BROKER_USERNAME=your_username PACT_BROKER_PASSWORD=your_password PACT_BROKER_URL=your_broker_url make test-pacts
...
(.venv) ➜  api-server git:(fix/pact-tests) ✗ make test-pacts

Dev-ops

None