feat(tui): add adaptive session tabs (#39396)

packages/tui/test/ui/animation.test.ts

@@ -0,0 +1,45 @@
+import { expect, test } from "bun:test"
+import { createRoot } from "solid-js"
+import { createAnimatable, spring, tween } from "../../src/ui/animation"
+
+test("animates numeric objects and arrays to their targets", async () => {
+  let dispose = () => {}
+  const visual = createRoot((nextDispose) => {
+    dispose = nextDispose
+    return createAnimatable(
+      { widths: [8, 8], selection: 0 },
+      { transition: tween({ duration: 0.02, ease: (progress) => progress }) },
+    )
+  })
+
+  try {
+    visual.animate({ widths: [12, 4], selection: 1 })
+    await Bun.sleep(80)
+    expect(visual.value()).toEqual({ widths: [12, 4], selection: 1 })
+  } finally {
+    dispose()
+  }
+})
+
+test("retains spring state while retargeting and supports immediate jumps", async () => {
+  let dispose = () => {}
+  const visual = createRoot((nextDispose) => {
+    dispose = nextDispose
+    return createAnimatable({ value: 0 }, { transition: spring({ visualDuration: 0.02 }) })
+  })
+
+  try {
+    visual.animate({ value: 1 })
+    await Bun.sleep(20)
+    const target = visual.value().value
+    visual.animate({ value: target })
+    await Bun.sleep(20)
+    expect(visual.value().value).not.toBe(target)
+    await Bun.sleep(80)
+    expect(visual.value().value).toBeCloseTo(target)
+    visual.jump({ value: 0 })
+    expect(visual.value().value).toBe(0)
+  } finally {
+    dispose()
+  }
+})