fix: mock remaining OpenCV GUI calls in tests to prevent guiReceiver error

[Sthitadhi1]

Problem

When running pytest or pre-commit hooks in headless environments (e.g., CI runners, containers, or environments without an active display server), the test suite fails with:

Root Cause

InteractionUtils.show() and is_window_available() in src/utils/interaction.py invoke cv2.namedWindow(), cv2.moveWindow(), and cv2.getWindowProperty(). Previously, setup_mocker_patches() in src/tests/utils.py only mocked cv2.imshow, cv2.destroyAllWindows, and cv2.waitKey. The three unmocked OpenCV GUI functions attempted real GUI window operations during testing, which fail in headless environments without a display backend.

Fix

Updated setup_mocker_patches(mocker) in src/tests/utils.py to add mocks for the remaining OpenCV GUI calls:

• cv2.namedWindow -> returns None
• cv2.moveWindow -> returns None
• cv2.getWindowProperty -> returns 1 (simulates window visibility)

No production code in src/utils/interaction.py was altered, preserving actual display runtime behavior for end users.

Testing Notes

• Verified locally via pytest and pre-commit that cv2.error: NULL guiReceiver (please create a window) is completely eliminated.
• Note: Snapshot test failures when running locally on Windows are due to pre-existing OS-specific path separator differences (\ vs /) and are unrelated to this OpenCV GUI mocking fix.

Fixes #230

[qodo-free-for-open-source-projects]

PR Summary by Qodo

Fix headless test failures by mocking remaining OpenCV GUI calls

🐞 Bug fix 🧪 Tests 🕐 Less than 10 minutes

AI Description

• Mock remaining OpenCV window APIs to prevent GUI calls during tests
• Eliminate NULL guiReceiver errors in headless CI/container environments
• Preserve production GUI behavior by limiting changes to test utilities

Diagram

graph TD
  A["Pytest suite"] --> B["src/tests/utils.py"] --> C["setup_mocker_patches()"] --> D["cv2 GUI APIs"]
  A --> E["entry_point_for_args()"] --> F["InteractionUtils.show() / is_window_available()"] --> D

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High-Level Assessment

The following are alternative approaches to this PR:

1. Use `opencv-python-headless` for test environments

• ➕ Avoids GUI backends entirely; fewer GUI-related runtime errors in CI
• ➕ Reduces need to mock individual GUI functions
• ➖ Can diverge from production dependency behavior
• ➖ May break code paths that rely on non-headless OpenCV builds in some environments

2. Add headless-guard logic in production interaction utilities

• ➕ Prevents GUI calls at runtime when no display is available
• ➕ Reduces reliance on tests to mock GUI behavior
• ➖ Changes production behavior (explicitly avoided in this PR)
• ➖ Requires robust headless detection across OSes and CI providers

Recommendation: Keep the current approach: targeted mocking in setup_mocker_patches() is the lowest-risk fix that addresses CI/headless failures without changing end-user runtime GUI behavior. Consider opencv-python-headless only if the project wants to standardize on headless execution for CI across the repo.

Files changed (1) +9 / -0

Tests (1) +9 / -0

utils.pyMock OpenCV window management calls in test patch setup +9/-0

Mock OpenCV window management calls in test patch setup

• Extends 'setup_mocker_patches()' to mock 'cv2.namedWindow', 'cv2.moveWindow', and 'cv2.getWindowProperty'. This prevents real window operations when tests exercise 'InteractionUtils.show()'/'is_window_available()' in headless environments.

src/tests/utils.py

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Code Review by Qodo

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