test: integration test dc solver fitness versus validation fitness

[Copilot]

This PR adds PST-focused integration coverage that cross-checks DC-solver fitness metrics against Powsybl-based validation, and introduces a new “parallel PST” example grid plus supporting fixture updates across packages.

Changes:

• Add new AC/DC integration tests comparing overload_energy_n_1 between DC solver aggregation and Powsybl runner validation for multiple PST scenarios.
• Introduce a new Powsybl example grid (parallel_pst_example) and corresponding preprocessed data-folder helper in dc_solver_pkg.
• Refactor/update test fixtures to rely on centralized example-grid preprocessing helpers (and rename a DC-solver test fixture).

Checklist

Please check if the PR fulfills these requirements:

• PR Title follows conventional commit messages
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• All commits in this PR are DCO signed-off (see CONTRIBUTING.md)

Does this PR already have an issue describing the problem?

Tracked by existing issue context in this PR flow.

What is the new behavior (if this is a feature change)?

Does this PR introduce a breaking change?

• Yes
• No

Original prompt

Start implementation

The user has attached the following file paths as relevant context:

• .github/copilot-instructions.md

[Chronological Review: The conversation began with the user reporting a failure in the test case `test_dc_optimizer_fitness_ac_validation_fitness_parallel_pst` due to discrepancies in the computation of N-1 overload energy between validation and the DC solver. The user requested to investigate the differences despite equal computations of N-1 loadflows. The user then indicated to start the implementation phase.]

[Intent Mapping:

• User reported a test failure: "This test case fails, due to a difference in the computation of N-1 overload energy..."
• User requested to investigate the discrepancy: "Figure out why there is a difference in the computation of metrics..."
• User indicated readiness to proceed with implementation: "Start implementation."]

[Technical Inventory:

• Technologies mentioned: pytest for testing, pypowsybl for network loading and DC load flow computations, and fsspec for file system operations.
• Key functions: parallel_pst_data_folder, load_grid, pypowsybl.network.load, pypowsybl.loadflow.run_dc, and net.save.
• Concepts: N-1 overload energy computation, validation metrics, and DC solver metrics.]

[Code Archaeology:

• File discussed: test_ac_dc_integration.py.
• Key function: test_dc_optimizer_fitness_ac_validation_fitness_parallel_pst, which sets up a test environment using a fixture and runs a DC load flow analysis.
• Recent code excerpt: fixture_name = "three_node_pst_example_data_folder" indicates the use of a specific data folder for testing.]

[Progress Assessment:

• Completed: User has identified a test case that fails due to metric discrepancies.
• Pending: Investigation into the differences in metric computations and implementation of solutions.]

[Context Validation: All necessary context for continuing the investigation into the test failure and the implementation of solutions is captured.]

[Recent Commands Analysis:

• Last Agent Commands: User requested to start implementation after identifying a test failure.
• Tool Results Summary: No specific tool results were returned as the focus was on the user's request to investigate and implement.
• Pre-Summary State: The agent was preparing to assist with the implementation phase after the user indicated readiness to proceed.
• Operation Context: The commands were executed in the context of addressing a test failure and preparing for implementation.]

1. Conversation Overview: - Primary Objectives: User aims to resolve a test failure in `test_dc_optimizer_fitness_ac_validation_fitness_parallel_pst` due to discrepancies in N-1 overload energy computations. User requested to investigate the differences and indicated readiness to start implementation. - Session Context: The conversation transitioned from identifying a test failure to preparing for implementation. - User Intent Evolution: Initially focused on troubleshooting the test failure, the user shifted to readiness for implementation.

2. Technical Foundation:

• pytest: Used for testing framework.
• pypowsybl: Library for network loading and DC load flow computations.
• fsspec: Used for file system operations.

3. Codebase Status:

• File Name: test_ac_dc_integration.py
• Purpose: Contains tests for DC optimizer fitness validation.
• Current State: User is investigating a failure in the test case.
• Key Code Segments:
  • def test_dc_optimizer_fitness_ac_validation_fitness_parallel_pst(tmp_path_factory: pytest.TempPathFactory) -> None: sets up the test environment.
  • fixture_name = "three_node_pst_example_data_folder" indicates the data folder used for testing.
• Dependencies: Relies on pypowsybl for network operations and fsspec for file handling.

4. Problem Resolution:

• Issues Encountered: Discrepancy in N-1 overload energy computations between validation and DC solver.
• Solutions Implemented: None yet, as the user is in the investigation phase.
• Debugging Context: Ongoing analysis of metric computation differences.
• Lessons Learned: Understanding of how different metrics can yield discrepancies despite similar loadflow computations.

5. Progress Tracking:

• Completed Tasks: Identification of the test failure.
• Partially Complete Work: Investigation into metric discrepancies is ongoing.
• Validated Outcomes: None confirmed yet as the investigation is still in progress.

6. Active Work State:

• Current Focus: Investigating the differences in metric computations related to the test failure.
• Recent Context: User indicated readiness to start implementation after identifying the issue.
• Working Code: The test function test_dc_optimizer_fitness_ac_validation_fitness_parallel_pst is the focus of the investigation.
• Immediate Context: User is looking to understand why the metrics differ despite equal computations.

7. Recent Operations:

• Last Agent Commands: User requested to sta...

Created from VS Code.

[spetznick-elia]

lgtm

[LeonHilf]

lgtm

[Copilot]

Pull request overview

This PR adds PST-focused integration coverage that cross-checks DC-solver fitness/overload metrics against Powsybl-based validation, and introduces a new “parallel PST” example grid plus supporting preprocessing helpers and fixture refactors across packages.

Changes:

• Added new AC/DC integration tests comparing overload_energy_n_1 between DC-solver aggregation and Powsybl validation across multiple PST scenarios.
• Introduced a new parallel_pst_example() Powsybl grid and new centralized “preprocessed data-folder” helper functions in dc_solver_pkg.
• Updated/centralized fixtures and added targeted preprocessing tests (e.g., operational-limit side voltage handling).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
packages/topology_optimizer_pkg/tests/test_ac_dc_integration.py	Adds integration tests that compare DC-solver metric aggregation vs Powsybl validation across PST tap scenarios.
packages/topology_optimizer_pkg/tests/conftest.py	Refactors grid-prep fixtures to rely on centralized preprocessing helpers.
packages/grid_helpers_pkg/src/toop_engine_grid_helpers/powsybl/example_grids.py	Adds the new parallel_pst_example() grid definition used for PST integration coverage.
packages/dc_solver_pkg/tests/test_example_grids.py	Extends example-grid tests, including coverage for complex-grid creation.
packages/dc_solver_pkg/tests/preprocessing/test_powsybl_helpers.py	Adds a regression test ensuring operational-limit “side” drives voltage used in get_p_max.
packages/dc_solver_pkg/tests/preprocessing/test_powsybl_backend.py	Updates fixture usage for complex-grid preprocessing/loadflow matching tests.
packages/dc_solver_pkg/tests/conftest.py	Refactors complex-grid fixtures to reuse centralized preprocessing helpers and persist network_data.pkl.
packages/dc_solver_pkg/src/toop_engine_dc_solver/preprocess/powsybl/powsybl_helpers.py	Updates get_p_max to use operational-limit side-specific voltage when converting current limits to MW.
packages/dc_solver_pkg/src/toop_engine_dc_solver/jax/nodal_inj_optim.py	Updates a comment in PST tap application code path (and introduces a TODO about sign).
packages/dc_solver_pkg/src/toop_engine_dc_solver/example_grids.py	Adds centralized helper(s) to generate preprocessed data folders for complex/parallel PST grids.

[LeonHilf]

lgtm

[sonarqube-mccs]

Quality Gate passed

Issues
1 New issue
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
87.5% Coverage on New Code
4.4% Duplication on New Code

See analysis details on SonarQube