summaryrefslogtreecommitdiffhomepage
path: root/src/features/smart-scroll/ui/controller.test.ts
diff options
context:
space:
mode:
Diffstat (limited to 'src/features/smart-scroll/ui/controller.test.ts')
-rw-r--r--src/features/smart-scroll/ui/controller.test.ts296
1 files changed, 148 insertions, 148 deletions
diff --git a/src/features/smart-scroll/ui/controller.test.ts b/src/features/smart-scroll/ui/controller.test.ts
index 614f4b0..906cc91 100644
--- a/src/features/smart-scroll/ui/controller.test.ts
+++ b/src/features/smart-scroll/ui/controller.test.ts
@@ -5,168 +5,168 @@ import { createSmartScrollController } from "./controller.svelte";
// geometry, scrollTo, and add/removeEventListener for "scroll"/"scrollend".
// Faking this outermost edge is the sanctioned mock (no internal modules mocked).
function createFakeScrollEl(opts?: { scrollHeight?: number; clientHeight?: number }) {
- const listeners = new Map<string, Set<EventListener>>();
- const el = {
- scrollTop: 0,
- scrollHeight: opts?.scrollHeight ?? 1000,
- clientHeight: opts?.clientHeight ?? 100,
- scrollTo: vi.fn((arg: ScrollToOptions) => {
- // Emulate the browser: jump scrollTop, then (for "instant") fire scrollend.
- el.scrollTop = (arg.top ?? 0) - 0;
- if (arg.behavior !== "smooth") {
- fire("scroll");
- fire("scrollend");
- }
- }),
- addEventListener: (type: string, fn: EventListener) => {
- if (!listeners.has(type)) listeners.set(type, new Set());
- listeners.get(type)?.add(fn);
- },
- removeEventListener: (type: string, fn: EventListener) => {
- listeners.get(type)?.delete(fn);
- },
- };
- function fire(type: string): void {
- for (const fn of listeners.get(type) ?? []) fn(new Event(type));
- }
- // Simulate the USER scrolling to a given offset (fires scroll, not self-driven).
- function userScrollTo(top: number): void {
- el.scrollTop = top;
- fire("scroll");
- }
- return {
- el: el as unknown as HTMLElement,
- scrollTo: el.scrollTo,
- fire,
- userScrollTo,
- listenerCount: () => listeners,
- };
+ const listeners = new Map<string, Set<EventListener>>();
+ const el = {
+ scrollTop: 0,
+ scrollHeight: opts?.scrollHeight ?? 1000,
+ clientHeight: opts?.clientHeight ?? 100,
+ scrollTo: vi.fn((arg: ScrollToOptions) => {
+ // Emulate the browser: jump scrollTop, then (for "instant") fire scrollend.
+ el.scrollTop = (arg.top ?? 0) - 0;
+ if (arg.behavior !== "smooth") {
+ fire("scroll");
+ fire("scrollend");
+ }
+ }),
+ addEventListener: (type: string, fn: EventListener) => {
+ if (!listeners.has(type)) listeners.set(type, new Set());
+ listeners.get(type)?.add(fn);
+ },
+ removeEventListener: (type: string, fn: EventListener) => {
+ listeners.get(type)?.delete(fn);
+ },
+ };
+ function fire(type: string): void {
+ for (const fn of listeners.get(type) ?? []) fn(new Event(type));
+ }
+ // Simulate the USER scrolling to a given offset (fires scroll, not self-driven).
+ function userScrollTo(top: number): void {
+ el.scrollTop = top;
+ fire("scroll");
+ }
+ return {
+ el: el as unknown as HTMLElement,
+ scrollTo: el.scrollTo,
+ fire,
+ userScrollTo,
+ listenerCount: () => listeners,
+ };
}
describe("smart-scroll controller", () => {
- it("starts with the button hidden", () => {
- const c = createSmartScrollController();
- expect(c.showButton).toBe(false);
- });
+ it("starts with the button hidden", () => {
+ const c = createSmartScrollController();
+ expect(c.showButton).toBe(false);
+ });
- it("contentChanged while stuck scrolls to the bottom instantly", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- c.attach(fake.el);
- c.contentChanged();
- expect(fake.scrollTo).toHaveBeenCalledWith({
- top: 1000,
- behavior: "instant",
- });
- expect(c.showButton).toBe(false);
- });
+ it("contentChanged while stuck scrolls to the bottom instantly", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ c.attach(fake.el);
+ c.contentChanged();
+ expect(fake.scrollTo).toHaveBeenCalledWith({
+ top: 1000,
+ behavior: "instant",
+ });
+ expect(c.showButton).toBe(false);
+ });
- it("a user scroll up shows the button and stops auto-following", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- c.attach(fake.el);
- fake.userScrollTo(200); // far from the bottom
- expect(c.showButton).toBe(true);
+ it("a user scroll up shows the button and stops auto-following", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ c.attach(fake.el);
+ fake.userScrollTo(200); // far from the bottom
+ expect(c.showButton).toBe(true);
- const scrollTo = fake.scrollTo;
- scrollTo.mockClear();
- c.contentChanged(); // streaming more content...
- expect(scrollTo).not.toHaveBeenCalled(); // ...must NOT yank the reader down
- expect(c.showButton).toBe(true);
- });
+ const scrollTo = fake.scrollTo;
+ scrollTo.mockClear();
+ c.contentChanged(); // streaming more content...
+ expect(scrollTo).not.toHaveBeenCalled(); // ...must NOT yank the reader down
+ expect(c.showButton).toBe(true);
+ });
- it("self-driven scrolls are not misread as the user scrolling up", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- c.attach(fake.el);
- // contentChanged drives an instant scrollTo, whose synthetic scroll event
- // must NOT flip us to unstuck (selfScrolling guard).
- c.contentChanged();
- expect(c.showButton).toBe(false);
- });
+ it("self-driven scrolls are not misread as the user scrolling up", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ c.attach(fake.el);
+ // contentChanged drives an instant scrollTo, whose synthetic scroll event
+ // must NOT flip us to unstuck (selfScrolling guard).
+ c.contentChanged();
+ expect(c.showButton).toBe(false);
+ });
- it("resume re-sticks and smooth-scrolls to the bottom", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- c.attach(fake.el);
- fake.userScrollTo(200);
- expect(c.showButton).toBe(true);
+ it("resume re-sticks and smooth-scrolls to the bottom", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ c.attach(fake.el);
+ fake.userScrollTo(200);
+ expect(c.showButton).toBe(true);
- c.resume();
- expect(fake.scrollTo).toHaveBeenCalledWith({
- top: 1000,
- behavior: "smooth",
- });
- expect(c.showButton).toBe(false);
- });
+ c.resume();
+ expect(fake.scrollTo).toHaveBeenCalledWith({
+ top: 1000,
+ behavior: "smooth",
+ });
+ expect(c.showButton).toBe(false);
+ });
- it("reset snaps to the bottom and hides the button", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- c.attach(fake.el);
- fake.userScrollTo(200);
- expect(c.showButton).toBe(true);
- c.reset();
- expect(fake.scrollTo).toHaveBeenCalledWith({
- top: 1000,
- behavior: "instant",
- });
- expect(c.showButton).toBe(false);
- });
+ it("reset snaps to the bottom and hides the button", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ c.attach(fake.el);
+ fake.userScrollTo(200);
+ expect(c.showButton).toBe(true);
+ c.reset();
+ expect(fake.scrollTo).toHaveBeenCalledWith({
+ top: 1000,
+ behavior: "instant",
+ });
+ expect(c.showButton).toBe(false);
+ });
- it("observes content via a ResizeObserver: follows growth while stuck, not while unstuck", () => {
- const holder: { cb: ResizeObserverCallback | null } = { cb: null };
- const observed: unknown[] = [];
- const disconnect = vi.fn();
- class FakeResizeObserver {
- constructor(cb: ResizeObserverCallback) {
- holder.cb = cb;
- }
- observe(target: Element): void {
- observed.push(target);
- }
- unobserve(): void {}
- disconnect = disconnect;
- }
- vi.stubGlobal("ResizeObserver", FakeResizeObserver);
- try {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- const content = { id: "content" } as unknown as HTMLElement;
- const teardown = c.attach(fake.el, content);
+ it("observes content via a ResizeObserver: follows growth while stuck, not while unstuck", () => {
+ const holder: { cb: ResizeObserverCallback | null } = { cb: null };
+ const observed: unknown[] = [];
+ const disconnect = vi.fn();
+ class FakeResizeObserver {
+ constructor(cb: ResizeObserverCallback) {
+ holder.cb = cb;
+ }
+ observe(target: Element): void {
+ observed.push(target);
+ }
+ unobserve(): void {}
+ disconnect = disconnect;
+ }
+ vi.stubGlobal("ResizeObserver", FakeResizeObserver);
+ try {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ const content = { id: "content" } as unknown as HTMLElement;
+ const teardown = c.attach(fake.el, content);
- // Observes both the content (it grows) and the scroll container (viewport resize).
- expect(observed).toContain(content);
- expect(observed).toContain(fake.el);
+ // Observes both the content (it grows) and the scroll container (viewport resize).
+ expect(observed).toContain(content);
+ expect(observed).toContain(fake.el);
- // Stuck → a resize keeps us pinned to the bottom.
- fake.scrollTo.mockClear();
- holder.cb?.([], {} as ResizeObserver);
- expect(fake.scrollTo).toHaveBeenCalledWith({ top: 1000, behavior: "instant" });
+ // Stuck → a resize keeps us pinned to the bottom.
+ fake.scrollTo.mockClear();
+ holder.cb?.([], {} as ResizeObserver);
+ expect(fake.scrollTo).toHaveBeenCalledWith({ top: 1000, behavior: "instant" });
- // Reader scrolls up → a later resize must NOT yank them down.
- fake.userScrollTo(200);
- fake.scrollTo.mockClear();
- holder.cb?.([], {} as ResizeObserver);
- expect(fake.scrollTo).not.toHaveBeenCalled();
+ // Reader scrolls up → a later resize must NOT yank them down.
+ fake.userScrollTo(200);
+ fake.scrollTo.mockClear();
+ holder.cb?.([], {} as ResizeObserver);
+ expect(fake.scrollTo).not.toHaveBeenCalled();
- // Teardown disconnects the observer.
- teardown();
- expect(disconnect).toHaveBeenCalled();
- } finally {
- vi.unstubAllGlobals();
- }
- });
+ // Teardown disconnects the observer.
+ teardown();
+ expect(disconnect).toHaveBeenCalled();
+ } finally {
+ vi.unstubAllGlobals();
+ }
+ });
- it("attach returns a teardown that removes both listeners", () => {
- const c = createSmartScrollController();
- const fake = createFakeScrollEl();
- const teardown = c.attach(fake.el);
- const before = fake.listenerCount();
- expect(before.get("scroll")?.size).toBe(1);
- expect(before.get("scrollend")?.size).toBe(1);
- teardown();
- expect(before.get("scroll")?.size).toBe(0);
- expect(before.get("scrollend")?.size).toBe(0);
- });
+ it("attach returns a teardown that removes both listeners", () => {
+ const c = createSmartScrollController();
+ const fake = createFakeScrollEl();
+ const teardown = c.attach(fake.el);
+ const before = fake.listenerCount();
+ expect(before.get("scroll")?.size).toBe(1);
+ expect(before.get("scrollend")?.size).toBe(1);
+ teardown();
+ expect(before.get("scroll")?.size).toBe(0);
+ expect(before.get("scrollend")?.size).toBe(0);
+ });
});
generated by cgit v1.2.3 (git 2.39.1) at 2026-07-11 19:21:07 +0000