Optimize pytest duplicate check from O(n) to O(1) using set

[Copilot]

The pytest hooks use a list to track collected tests and check for duplicates with if test_id not in collected_tests_so_far, which scales poorly for large test suites (O(n) per check).

Changes

• Changed collected_tests_so_far from list to set (line 78)
• Updated .append() calls to .add() in three hooks:
  • pytest_exception_interact() (line 173)
  • pytest_report_teststatus() (line 298)
  • pytest_runtest_protocol() (line 332)

Impact

Membership checks now O(1) average case instead of O(n). For a test suite with 1000 tests, this reduces duplicate checking from ~500,000 operations to ~1,000.

# Before: O(n) membership check
collected_tests_so_far = []
if test_id not in collected_tests_so_far:  # Linear scan
    collected_tests_so_far.append(test_id)

# After: O(1) membership check  
collected_tests_so_far = set()
if test_id not in collected_tests_so_far:  # Hash lookup
    collected_tests_so_far.add(test_id)

Original prompt

Start implementation

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

• .github/instructions/learning.instructions.md

[Chronological Review: The conversation began with the user requesting assistance to optimize pytest logic in a specific file. The user provided a code snippet and identified specific lines for optimization, suggesting the use of sets for duplicate checks to improve performance from O(n) to O(1). The user emphasized that while the hooks are not called during discovery, optimizing them is crucial for test execution performance in large test suites.]

[Intent Mapping: The user explicitly requested to "expand on" their idea of using sets for duplicate checks and to "plan it out." They specified the locations in the code where changes should be made and highlighted the performance implications of the current implementation.]

[Technical Inventory: The conversation involves the pytest framework, specifically focusing on performance optimization techniques. The user is working with Python's data structures, particularly lists and sets, to enhance execution speed.]

[Code Archaeology: The user referenced specific lines in the __init__.py file, particularly lines 173, 298, and 332, which contain the pytest_report_teststatus() and pytest_runtest_protocol() functions. The user provided a code snippet showing the current list check and suggested replacing it with a set for better performance.]

[Progress Assessment: The user has identified a specific optimization opportunity but has not yet implemented any changes. The conversation is in the planning phase, focusing on how to approach the optimization.]

[Context Validation: All critical information for continuation is captured, including the specific lines to modify and the rationale behind the optimization.]

[Recent Commands Analysis: The last agent command involved summarizing the conversation history. The tool results included the user's request for optimization and the context of the file being worked on. The immediate pre-summarization state involved discussing the optimization of pytest logic in the provided file.]

1. Conversation Overview: - Primary Objectives: The user requested to "help speed up my pytest logic in the attached file" by using sets for duplicate checks to improve performance. They specified the locations in the code for optimization. - Session Context: The conversation focused on identifying performance bottlenecks in pytest hooks and planning an optimization strategy. - User Intent Evolution: The user started with a specific optimization idea and is looking for a detailed plan to implement it.

2. Technical Foundation:

• [pytest]: [A testing framework for Python, used for writing simple and scalable test cases.]
• [Python Sets]: [Data structure that allows for O(1) average time complexity for membership checks, which the user wants to leverage for performance improvement.]

3. Codebase Status:

• [init.py]:
• Purpose: Contains pytest hook implementations that manage test execution and reporting.
• Current State: The user identified specific lines for optimization but no changes have been made yet.
• Key Code Segments:
  • pytest_report_teststatus(): Line 173
  • pytest_runtest_protocol(): Lines 298, 332
• Dependencies: These functions are integral to the pytest execution flow and impact performance during test runs.

4. Problem Resolution:

• Issues Encountered: Current implementation uses lists for duplicate checks, leading to O(n) performance.
• Solutions Implemented: The user proposed using sets to improve performance but has not yet implemented this solution.
• Debugging Context: No ongoing troubleshooting efforts were mentioned; the focus is on optimization.
• Lessons Learned: The user recognizes the importance of optimizing hooks for large test suites.

5. Progress Tracking:

• Completed Tasks: None yet; the user is in the planning phase.
• Partially Complete Work: The user has outlined an optimization strategy but has not executed it.
• Validated Outcomes: No features or code have been confirmed working through testing yet.

6. Active Work State:

• Current Focus: The user is focused on optimizing pytest logic by changing list checks to set checks.
• Recent Context: The user provided a code snippet and discussed the implications of the current implementation.
• Working Code: The user referenced specific lines in the __init__.py file for modification.
• Immediate Context: The user was actively discussing the optimization of pytest hooks when the token budget was exceeded.

7. Recent Operations:

• Last Agent Commands: The agent executed a summarization command to capture the conversation history.
• Tool Results Summary: The results included the user's request for optimization and the context of the file being worked on.
• Pre-Summary State: The agent was discussing the optimization of pytest logic in the provided file.
• Operation Context: The sum...

Created from VS Code.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[eleanorjboyd]

@copilot reset my local main to same as upstream main