test: add home top mask progress helper

2026-08-08 01:30:38 +08:00
parent fdd92924a5
commit 8ac8558142
2 changed files with 41 additions and 0 deletions
@@ -0,0 +1,30 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { getTopMaskProgress } from '../src/utils/homeTopMask.js'
+
+test('returns 0 before the title reaches the status-bar area', () => {
+  assert.equal(
+    getTopMaskProgress({ scrollTop: 30, startY: 80, rangeY: 40 }),
+    0
+  )
+})
+
+test('ramps linearly through the transition range', () => {
+  assert.equal(
+    getTopMaskProgress({ scrollTop: 100, startY: 80, rangeY: 40 }),
+    0.5
+  )
+})
+
+test('returns 1 after the full transition range', () => {
+  assert.equal(
+    getTopMaskProgress({ scrollTop: 180, startY: 80, rangeY: 40 }),
+    1
+  )
+})
+
+test('clamps invalid values into a stable progress range', () => {
+  assert.equal(getTopMaskProgress({ scrollTop: -10, startY: 80, rangeY: 40 }), 0)
+  assert.equal(getTopMaskProgress({ scrollTop: 90, startY: 80, rangeY: 0 }), 1)
+  assert.equal(getTopMaskProgress({ scrollTop: Number.NaN, startY: 80, rangeY: 40 }), 0)
+})