Appearance (window sizing) — Specs

Line coverage: AppearanceTestable.swift 79% · refreshed 2026-05-27 by /coverage-explore

Summary

Two pure sizing functions in AppearanceTestable decide how big the switcher's thumbnails are on a given display, so the UI feels right from an 11" laptop to a 60" TV. The suite pins their output against a table of 21 real device models (laptops, monitors, ultrawides, TVs) with known pixel + physical dimensions, so a tweak to the formula can't silently regress any class of screen.

• comfortableWidth(physicalDimension) → the fraction of the screen the switcher should occupy (smaller fraction on bigger/wider screens, separate expectations for horizontal vs vertical use).
• goodValuesForThumbnailsWidthMinMax(ratio, rowCount) → the (min, max) thumbnail width for a given screen aspect ratio and row count (3, 4, or 5 rows).

Behavior & edge cases

• Driven entirely by a fixture table: each row is (model, pixels, physical-mm, expected comfortable fractions, [(rowCount, expectedMin, expectedMax)]). Both tests loop the table and assert with 0.01 tolerance, naming the failing model.
• Bigger physical screens get a smaller comfortable fraction (a 60" TV shouldn't show a half-screen switcher); ultrawides get distinct horizontal vs vertical fractions.

Test scenarios

Mirrors AppearanceTests.swift 1:1.

• testGoodValuesForThumbnailsWidthMinMax — for every model × {3,4,5} rows, the computed (min, max) thumbnail width matches the fixture.
• testComfortableWidth — for every model, the comfortable width fraction matches for both horizontal and vertical screen use.
• testComfortableWidthFallsBackToDefaultWhenPhysicalWidthIsNil — when the screen's physical dimensions aren't reported, fall back to the 0.9 default rather than the 0.45 floor.
• testGoodValuesForThumbnailsWidthMinMaxPortrait — for aspectRatio < 1 (portrait usage), the (min, max) uses the portrait formula and stays within the [0.09, 0.30] clamps.