feat: Improve existing numeric metrics for new output format

[Moritz Potthoff (MoritzPotthoffQC)]

Motivation

It would be nice to apply the new output format of #43 (<old> -> <new> (<delta>)) also to all existing metrics where it makes sense.

Changes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (eb1c427) to head (4c3e7cc).

Additional details and impacted files

@@                         Coverage Diff                          @@
##           generalize-metrics-add-nullability       #44   +/-   ##
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  Coverage                              100.00%   100.00%           
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  Files                                      11        11           
  Lines                                    1030      1035    +5     
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+ Hits                                     1030      1035    +5     

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[Copilot]

Pull request overview

This PR updates Diffly’s metric outputs to use the newer “old -> new (delta)” rendering for existing numeric metrics, and propagates that change through unit tests and golden summary fixtures (including CLI-visible metric labels).

Changes:

• Update tests/test_metrics.py expectations for numeric preset metrics to assert formatted change strings (e.g., 2.0 -> 3.0 (+1.0)).
• Update summary.to_json() expectations and many golden summary fixtures to reflect the new rendered metric values/layout.
• Rename the null-fraction preset label used in tests/fixtures/CLI from ΔNull% to Null%.

Reviewed changes

Copilot reviewed 165 out of 165 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/test_metrics.py	Updates metric unit tests to expect formatted <old> -> <new> (<delta>) strings for numeric presets.
tests/summary/test_summary.py	Updates JSON summary expectations for metrics to match new rendered string values.
tests/cli/test_cli.py	Updates CLI test to request/display the renamed null-fraction metric preset (Null%).
tests/summary/fixtures/metrics_null_fraction/test_metrics_null_fraction.py	Updates fixture generator test to use the renamed null-fraction preset label (Null%).
tests/summary/fixtures/metrics_presets_many/gen/*.txt	Regenerates golden fixtures to reflect new metric rendering and resulting table wrapping.
tests/summary/fixtures/metrics_presets_few/gen/*.txt	Regenerates golden fixtures to reflect new metric rendering and resulting table wrapping.
tests/summary/fixtures/metrics_null_fraction/gen/*.txt	Regenerates golden fixtures for null-fraction metrics to reflect the new label and rendering.
tests/summary/fixtures/metrics_long_labels/gen/*.txt	Regenerates golden fixtures to reflect new metric rendering under long-header layout constraints.
tests/summary/fixtures/metrics_custom/gen/*.txt	Regenerates golden fixtures to reflect new metric rendering for user-supplied metrics.

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[Copilot]

Pull request overview

Copilot reviewed 163 out of 163 changed files in this pull request and generated 1 comment.