Refactor axis sharing logic and improve test coverage for UltraPlot

[cvanelteren]

Closes #348

This PR refactors axis sharing logic and adds comprehensive tests to improve coverage and robustness across UltraPlot’s core plotting modules.

Key Changes

Core Logic

• Refactored axis sharing checks in GeoAxes and Figure:

  • Replaced usage of _get_sharing_level() with direct checks on _sharex and _sharey for clarity and correctness.
  • Updated axis sharing logic to use the correct sharing level for each axis (x or y), ensuring more precise control over label and tick sharing.
  • Improved handling of axis sharing for geographic axes, passing the which argument to clarify axis context.

• Removed unused method: _get_sharing_level() from Figure.

Tests

• Added new tests in test_figure.py:

  • Coverage for _get_renderer to ensure renderer acquisition works as expected.
  • Coverage for _share_labels_with_others, including both early return (no sharing) and execution with sharing enabled.

• Added new tests in test_sharing.py:

  • Parametrized tests for x and y axis sharing levels, verifying correct label and tick visibility for all sharing modes and Matplotlib versions.
  • Ensures border axes are correctly detected and labels/ticks are only visible where appropriate.

• Improved tests in test_geographic.py:

  • Parametrized sharing level tests for geographic axes, ensuring correct sharing of limits and labels.

Why?

• Improved clarity and maintainability: Directly checking _sharex and _sharey makes the code easier to understand and less error-prone.
• Better test coverage: Addresses previously uncovered lines and branches, as highlighted by Codecov.
• More robust axis sharing: Ensures correct behavior for all sharing levels, including edge cases and version differences in Matplotlib.

[codecov]

Codecov Report

❌ Patch coverage is 90.25271% with 27 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ultraplot/figure.py	89.68%	6 Missing and 7 partials ⚠️
ultraplot/utils.py	82.14%	4 Missing and 1 partial ⚠️
ultraplot/tests/test_sharing.py	92.98%	2 Missing and 2 partials ⚠️
ultraplot/gridspec.py	40.00%	2 Missing and 1 partial ⚠️
ultraplot/axes/base.py	50.00%	1 Missing ⚠️
ultraplot/axes/polar.py	85.71%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[Copilot]

Pull Request Overview

This PR refactors axis sharing logic in UltraPlot by replacing a centralized sharing level method with direct checks on sharing attributes, and adds comprehensive test coverage for axis sharing behavior across different modules.

• Removes the _get_sharing_level() method and replaces its usage with direct checks on _sharex and _sharey attributes
• Adds parametrized tests for axis sharing levels in both regular and geographic plotting contexts
• Improves test coverage for renderer acquisition and label sharing methods

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
ultraplot/tests/test_sharing.py	New comprehensive test file covering x/y axis sharing levels with parametrized tests
ultraplot/tests/test_geographic.py	Converts sharing level test to parametrized format and updates sharing logic reference
ultraplot/tests/test_figure.py	Adds tests for renderer acquisition and label sharing methods
ultraplot/figure.py	Removes _get_sharing_level() method and updates sharing checks to use direct attribute access
ultraplot/axes/geo.py	Updates axis sharing logic to use direct sharing level checks and adds which parameter

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[cvanelteren]

Ok 19 tests left to fix, but some of them look good anyway. There are some things that needs fixing.

Primarily, I need to look at the interface between geo and cartesian panels.