Add custom test runner for parallel/serial execution of WebSocket and Selenium tests

[Copilot]

Problem

When running tests with the --parallel flag, WebSocket tests (inheriting from ChannelsLiveServerTestCase) and Selenium tests (inheriting from StaticLiveServerTestCase) can experience port conflicts and connection issues due to concurrent execution. This leads to flaky test failures and unreliable CI/CD pipelines.

Solution

This PR introduces a custom test runner ChannelsParallelTestRunner that intelligently separates test execution:

1. First runs regular tests in parallel - Model tests, API tests, admin tests, etc.
2. Then runs WebSocket/Selenium tests serially - Prevents port conflicts and connection issues

Implementation

Core Features

• Automatic Detection: Identifies test cases inheriting from:

  • channels.testing.ChannelsLiveServerTestCase
  • django.contrib.staticfiles.testing.StaticLiveServerTestCase

• Smart Execution:

  • Without --parallel: All tests run serially (no behavior change)
  • With --parallel: Splits execution into parallel then serial phases

• Backward Compatible: Zero configuration changes required, existing tests work unchanged

Code Changes

1. Enhanced MockRequestPostRunner in openwisp_utils/metric_collection/tests/runner.py:

   • Now inherits from ChannelsParallelTestRunner
   • Maintains existing usage metrics mocking functionality
   • Adds intelligent test execution logic

2. New ChannelsParallelTestRunner class:

   • Detects WebSocket test cases automatically
   • Splits test suites when parallel execution is requested
   • Manages execution order and result merging

3. Comprehensive test suite in openwisp_utils/metric_collection/tests/test_runner.py:

   • 11 test methods covering detection logic, suite splitting, and edge cases
   • Validates behavior with different test case types

4. Documentation in docs/developer/test-runner.rst:

   • Usage examples and technical implementation details

Example Output

$ python runtests.py --parallel 4
Found 150 test(s).
Creating test database...
Running 130 regular tests in parallel...
...
Running 20 WebSocket/Selenium tests serially...
...

Benefits

• 🚀 Improved Performance: Regular tests still benefit from parallel execution
• 🔧 Increased Reliability: Eliminates port conflicts in WebSocket/Selenium tests
• ⚡ Zero Config: Automatic detection requires no manual test categorization
• 🔄 Backward Compatible: Existing workflows unchanged

Testing

The implementation includes comprehensive unit tests that verify:

• Correct detection of different test case types
• Proper suite splitting with nested test suites
• Handling of edge cases (empty suites, mixed types)
• Integration with existing test infrastructure

This change addresses the original issue while maintaining full compatibility with the existing test ecosystem.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• openwisp.org
  • Triggering command: python runtests.py test_project.tests.test_model -v 2 (dns block)
  • Triggering command: python runtests.py test_project.tests.test_model --parallel 2 -v 2 (dns block)
  • Triggering command: python runtests.py test_project.tests.test_model test_project.tests.test_selenium.TestMenu --parallel 2 -v 2 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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