Files
paseo/packages/app/src/agent-stream/strategy-web.test.tsx
T
Mohamed Boudra 9131505810 Fill short collapsed chat histories (#8358)
* fix(app): fill short collapsed chat histories

Collapsed whole turns can leave the initial viewport short even when older history exists. Continue paging through measured pages before revealing a fresh chat, while preserving visible history and the reading anchor.

* fix(app): settle padded and stalled chat history

Measure the native history edge using the same content area as viewport filling, and bound child history requests so retry can start after a stalled fetch.

* fix(app): adapt viewport filling to the current timeline

* fix(app): resume history filling after switching tabs
2026-11-07 23:12:08 +07:00

1664 lines
56 KiB
TypeScript

/**
* @vitest-environment jsdom
*/
import { DEFAULT_CONTENT_MAX_WIDTH } from "@/styles/theme";
import React from "react";
import { act } from "react";
import { createRoot, type Root } from "react-dom/client";
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { RetainedPanelActivity } from "@/components/retained-panel";
import { reduceStreamUpdate, type StreamItem } from "@/types/stream";
import type { StreamRenderInput, StreamSegmentRenderers, StreamViewportHandle } from "./strategy";
import { createWebStreamStrategy } from "./strategy-web";
vi.hoisted(() => {
Object.defineProperty(window, "matchMedia", {
configurable: true,
value: () => ({
addEventListener: () => {},
addListener: () => {},
dispatchEvent: () => false,
matches: false,
media: "",
onchange: null,
removeEventListener: () => {},
removeListener: () => {},
}),
});
});
vi.mock("react-native-unistyles", () => ({
StyleSheet: { create: () => ({}) },
withUnistyles: (Component: React.ComponentType) => Component,
}));
function userMessage(index: number): Extract<StreamItem, { kind: "user_message" }> {
return {
kind: "user_message",
id: `message-${index}`,
text: `Message ${index}`,
timestamp: new Date(`2026-04-20T00:00:${String(index % 60).padStart(2, "0")}.000Z`),
};
}
const VIRTUAL_ROW_STYLE = { height: 24 };
function createRenderers(onRowRender: () => void): StreamSegmentRenderers {
return {
renderHistoryVirtualizedRow: (item) => {
onRowRender();
return <div style={VIRTUAL_ROW_STYLE}>{item.id}</div>;
},
renderHistoryMountedRow: (item) => <div>{item.id}</div>,
renderLiveHeadRow: (item) => <div>{item.id}</div>,
renderLiveAuxiliary: () => null,
};
}
function MeasuredTestRow({ item }: { item: StreamItem }) {
const [loaded, setLoaded] = React.useState(false);
const load = React.useCallback(() => setLoaded(true), []);
const height = item.kind === "user_message" && item.text === "grown" ? 120 : 24;
const measure = React.useCallback(
(node: HTMLDivElement | null) => {
if (!node?.parentElement) return;
Object.defineProperty(node.parentElement, "offsetHeight", {
configurable: true,
value: height,
});
},
[height],
);
return (
<div ref={measure}>
<button type="button" onClick={load}>
{loaded ? "Loaded" : "Load"}
</button>
{item.id}
</div>
);
}
describe("createWebStreamStrategy", () => {
let root: Root | null = null;
let container: HTMLDivElement | null = null;
let originalScrollTo: HTMLElement["scrollTo"] | undefined;
let originalOffsetHeight: PropertyDescriptor | undefined;
beforeEach(() => {
Object.defineProperty(globalThis, "IS_REACT_ACT_ENVIRONMENT", {
value: true,
configurable: true,
});
Object.defineProperty(globalThis, "ResizeObserver", {
value: class ResizeObserver {
observe() {}
unobserve() {}
disconnect() {}
},
configurable: true,
});
originalScrollTo = HTMLElement.prototype.scrollTo;
HTMLElement.prototype.scrollTo = vi.fn();
originalOffsetHeight = Object.getOwnPropertyDescriptor(HTMLElement.prototype, "offsetHeight");
Object.defineProperty(HTMLElement.prototype, "offsetHeight", {
configurable: true,
get() {
return 24;
},
});
});
afterEach(() => {
if (root) {
act(() => {
root?.unmount();
});
}
root = null;
container?.remove();
container = null;
if (originalScrollTo) {
HTMLElement.prototype.scrollTo = originalScrollTo;
} else {
Reflect.deleteProperty(HTMLElement.prototype, "scrollTo");
}
if (originalOffsetHeight) {
Object.defineProperty(HTMLElement.prototype, "offsetHeight", originalOffsetHeight);
} else {
Reflect.deleteProperty(HTMLElement.prototype, "offsetHeight");
}
vi.restoreAllMocks();
});
it.each(["liveHead", "historyMounted"] as const)(
"keeps one rendered tool row after late prior-turn updates in %s",
(lane) => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
const input: StreamRenderInput = {
agentId: "agent",
segments: { historyVirtualized: [], historyMounted: [], liveHead: [] },
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: lane === "historyMounted",
hasLiveHead: lane === "liveHead",
},
renderers: createRenderers(() => {}),
listEmptyComponent: null,
viewportRef: React.createRef<StreamViewportHandle>(),
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: () => {},
onNearHistoryStart: async () => true,
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
let items: StreamItem[] = [];
const updates = [
{ callId: "background", turnId: "old", status: "running" },
{ callId: "exec", turnId: "current", status: "running" },
{ callId: "background", turnId: "old", status: "completed" },
{ callId: "exec", turnId: "current", status: "completed" },
] as const;
for (const [index, update] of updates.entries()) {
items = reduceStreamUpdate(
items,
{
type: "timeline",
provider: "codex",
turnId: update.turnId,
item: {
type: "tool_call",
callId: update.callId,
name: "exec_command",
status: update.status,
error: null,
detail: { type: "shell", command: update.callId },
},
},
new Date(index),
);
act(() =>
root?.render(
strategy.render({
...input,
segments: { ...input.segments, [lane]: items },
}),
),
);
}
const rows = [...container.querySelectorAll("[data-history-row-id]")];
expect(rows.map((row) => row.getAttribute("data-history-row-id"))).toEqual([
"agent_tool_turn:old/background",
"agent_tool_turn:current/exec",
]);
},
);
it("mounts virtualized history without recursive row measurement updates", () => {
const rowRenderCount = vi.fn();
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const historyVirtualized = Array.from({ length: 16 }, (_, index) => userMessage(index));
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
<>
{strategy.render({
agentId: "agent",
segments: {
historyVirtualized,
historyMounted: [],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: true,
hasMountedHistory: false,
hasLiveHead: false,
},
renderers: createRenderers(rowRenderCount),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
})}
</>,
);
});
expect(rowRenderCount.mock.calls.length).toBeGreaterThan(0);
expect(rowRenderCount.mock.calls.length).toBeLessThanOrEqual(historyVirtualized.length);
});
it("retains a row's DOM and local state when recent history becomes virtualized", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
const item = userMessage(0);
const renderRow = (rowItem: StreamItem) => <MeasuredTestRow item={rowItem} />;
const input: StreamRenderInput = {
agentId: "agent",
segments: { historyVirtualized: [], historyMounted: [item], liveHead: [] },
boundary: { hasVirtualizedHistory: false, hasMountedHistory: true, hasLiveHead: false },
renderers: {
renderHistoryVirtualizedRow: renderRow,
renderHistoryMountedRow: renderRow,
renderLiveHeadRow: renderRow,
renderLiveAuxiliary: () => null,
},
listEmptyComponent: null,
viewportRef: React.createRef<StreamViewportHandle>(),
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: () => {},
onNearHistoryStart: async () => true,
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
act(() => root?.render(strategy.render(input)));
const row = container.querySelector('[data-history-row-id="message-0"]')!;
act(() => row.querySelector("button")!.click());
expect(row.querySelector("button")!.textContent).toBe("Loaded");
const viewport = container.querySelector('[data-testid="agent-chat-scroll"]')!;
Object.defineProperty(viewport, "clientHeight", { configurable: true, value: 500 });
act(() =>
root?.render(
strategy.render({
...input,
segments: { historyVirtualized: [item], historyMounted: [userMessage(1)], liveHead: [] },
boundary: { ...input.boundary, hasVirtualizedHistory: true },
}),
),
);
expect(container.querySelector('[data-history-row-id="message-0"]')).toBe(row);
expect(row.isConnected).toBe(true);
expect(row.querySelector("button")!.textContent).toBe("Loaded");
act(() =>
root?.render(
strategy.render({
...input,
segments: {
historyVirtualized: [{ ...item, text: "grown" }, userMessage(1)],
historyMounted: [userMessage(2)],
liveHead: [],
},
boundary: { ...input.boundary, hasVirtualizedHistory: true },
}),
),
);
expect(
(container.querySelector('[data-history-row-id="message-1"]') as HTMLElement).style.transform,
).toBe("translateY(120px)");
expect(row.querySelector("button")!.textContent).toBe("Loaded");
});
it("keeps the timeline width stable with an overlay scrollbar", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef: React.createRef<StreamViewportHandle>(),
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
}),
);
});
const scrollContainer = container.querySelector<HTMLElement>(
'[data-testid="agent-chat-scroll"]',
);
expect(scrollContainer?.style.scrollbarWidth).toBe("none");
expect(scrollContainer?.dataset.overlayScrollbar).toBe("true");
});
it("rerenders a stable live-head row when its revision changes", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
const viewportRef = React.createRef<StreamViewportHandle>();
const liveHead = [userMessage(1)];
let label = "collapsed";
const renderLiveHeadRow = vi.fn(() => <div>{label}</div>);
const renderInput: StreamRenderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [],
liveHead,
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: false,
hasLiveHead: true,
},
renderers: {
...createRenderers(vi.fn()),
renderLiveHeadRow,
},
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(strategy.render({ ...renderInput, liveHeadRowRevision: 0 }));
});
expect(container.textContent).toContain("collapsed");
label = "expanded";
act(() => {
root?.render(strategy.render({ ...renderInput, liveHeadRowRevision: 1 }));
});
expect(container.textContent).toContain("expanded");
expect(renderLiveHeadRow).toHaveBeenCalledTimes(2);
});
it("rerenders only the history row whose content revision changed", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
const viewportRef = React.createRef<StreamViewportHandle>();
const host = userMessage(1);
const other = userMessage(2);
const renderCountById = new Map<string, number>();
const HistoryRow = React.memo(function HistoryRow({ item }: { item: StreamItem }) {
renderCountById.set(item.id, (renderCountById.get(item.id) ?? 0) + 1);
return <div>{item.id}</div>;
});
const renderInput: StreamRenderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [host, other],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: {
...createRenderers(vi.fn()),
renderHistoryMountedRow: (item) => <HistoryRow item={item} />,
},
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
const unrevised = {
contentById: new Set<string>(),
displayStateById: new Set<string>(),
globalDisplayState: false,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(strategy.render({ ...renderInput, historyRowRevision: unrevised }));
});
expect(renderCountById.get(host.id)).toBe(1);
expect(renderCountById.get(other.id)).toBe(1);
act(() => {
root?.render(
strategy.render({
...renderInput,
historyRowRevision: { ...unrevised, contentById: new Set([host.id]) },
}),
);
});
expect(renderCountById.get(host.id)).toBe(2);
expect(renderCountById.get(other.id)).toBe(1);
});
it("keeps a row mounted when it moves from the live head into mounted history", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
const viewportRef = React.createRef<StreamViewportHandle>();
const item = userMessage(1);
const mounted = vi.fn();
const unmounted = vi.fn();
function StatefulRow() {
React.useEffect(() => {
mounted();
return unmounted;
}, []);
return <div>{item.id}</div>;
}
const renderers: StreamSegmentRenderers = {
...createRenderers(vi.fn()),
renderHistoryMountedRow: () => <StatefulRow />,
renderLiveHeadRow: () => <StatefulRow />,
};
const renderInput: Omit<StreamRenderInput, "segments" | "boundary"> = {
agentId: "agent",
renderers,
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: { historyVirtualized: [], historyMounted: [], liveHead: [item] },
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: false,
hasLiveHead: true,
},
}),
);
});
expect(mounted).toHaveBeenCalledTimes(1);
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: { historyVirtualized: [], historyMounted: [item], liveHead: [] },
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
}),
);
});
expect(mounted).toHaveBeenCalledTimes(1);
expect(unmounted).not.toHaveBeenCalled();
});
it("reports the live-head row as the reading position", () => {
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
const viewportRef = React.createRef<StreamViewportHandle>();
const onReadingPositionChange = vi.fn();
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1)],
liveHead: [userMessage(2)],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: true,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onReadingPositionChange,
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
}),
);
});
expect(onReadingPositionChange).toHaveBeenLastCalledWith("message-2");
});
it("keeps bottom anchoring through subpixel browser rounding", () => {
const scrollTo = vi.fn();
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: false });
const viewportRef = React.createRef<StreamViewportHandle>();
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
}),
);
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 766 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 5725 });
scrollContainer.scrollTop = 4959.1708984375;
scrollTo.mockClear();
act(() => {
viewportRef.current?.scrollToBottom("message-sent");
});
expect(scrollTo).toHaveBeenCalledWith({ top: 5725, behavior: "auto" });
scrollTo.mockClear();
scrollContainer.scrollTop = 4960.5;
act(() => {
viewportRef.current?.scrollToBottom("message-sent");
});
expect(scrollTo).toHaveBeenCalledWith({ top: 5725, behavior: "auto" });
scrollTo.mockClear();
scrollContainer.scrollTop = 4967;
act(() => {
viewportRef.current?.scrollToBottom("message-sent");
});
expect(scrollTo).not.toHaveBeenCalled();
});
it("waits for bottom anchoring before evaluating a delayed initial tail", async () => {
HTMLElement.prototype.scrollTo = vi.fn(function (
this: HTMLElement,
options?: ScrollToOptions | number,
y?: number,
) {
const top = typeof options === "object" ? (options.top ?? 0) : (y ?? 0);
this.scrollTop = top;
});
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const onNearHistoryStart = vi.fn().mockReturnValue(true);
const renderInput = {
agentId: "agent",
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: false,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart,
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: { historyVirtualized: [], historyMounted: [], liveHead: [] },
}),
);
});
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 400 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1200 });
scrollContainer.scrollTop = 0;
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1), userMessage(2)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
hasOlderHistory: true,
olderHistoryProgressKey: "epoch-1:20",
}),
);
});
expect(onNearHistoryStart).not.toHaveBeenCalled();
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
expect(onNearHistoryStart).not.toHaveBeenCalled();
});
it("keeps initial route entry anchored when delayed route readiness arrives before user scroll", async () => {
const scrollTo = vi.fn(function (
this: HTMLElement,
options?: ScrollToOptions | number,
y?: number,
) {
const top = typeof options === "object" ? (options.top ?? 0) : (y ?? 0);
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const routeBottomAnchorRequest = {
agentId: "agent",
reason: "initial-entry" as const,
requestKey: "server:agent:initial-entry",
};
const renderInput = {
agentId: "agent",
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: false,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
historyVirtualized: [],
historyMounted: [],
liveHead: [],
},
isAuthoritativeHistoryReady: false,
}),
);
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
const scrollElement = scrollContainer;
Object.defineProperty(scrollElement, "clientHeight", { configurable: true, value: 400 });
Object.defineProperty(scrollElement, "scrollHeight", { configurable: true, value: 400 });
scrollElement.scrollTop = 0;
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
scrollTo.mockClear();
const historyMounted = Array.from({ length: 20 }, (_, index) => userMessage(index));
Object.defineProperty(scrollElement, "scrollHeight", { configurable: true, value: 1400 });
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
historyVirtualized: [],
historyMounted,
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
isAuthoritativeHistoryReady: true,
}),
);
});
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
expect(scrollTo).toHaveBeenCalled();
expect(scrollElement.scrollTop).toBe(1400);
});
it("does not force bottom on delayed route readiness after the user scrolls away", async () => {
const scrollTo = vi.fn(function (
this: HTMLElement,
options?: ScrollToOptions | number,
y?: number,
) {
const top = typeof options === "object" ? (options.top ?? 0) : (y ?? 0);
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const historyMounted = Array.from({ length: 20 }, (_, index) => userMessage(index));
const onNearHistoryStart = vi.fn().mockReturnValue(false);
const routeBottomAnchorRequest = {
agentId: "agent",
reason: "initial-entry" as const,
requestKey: "server:agent:initial-entry",
};
const renderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted,
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest,
onNearBottomChange: vi.fn(),
onNearHistoryStart,
isLoadingOlderHistory: false,
hasOlderHistory: true,
olderHistoryProgressKey: "epoch-1:20",
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
isAuthoritativeHistoryReady: false,
}),
);
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 400 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1400 });
scrollContainer.scrollTop = 1000;
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
scrollTo.mockClear();
act(() => {
scrollContainer.dispatchEvent(new WheelEvent("wheel", { deltaY: -240 }));
});
scrollContainer.scrollTop = 0;
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
expect(scrollTo).not.toHaveBeenCalled();
act(() => {
root?.render(
strategy.render({
...renderInput,
isAuthoritativeHistoryReady: true,
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
await act(async () => Promise.resolve());
expect(onNearHistoryStart).toHaveBeenCalledOnce();
act(() => {
scrollContainer.dispatchEvent(new WheelEvent("wheel", { deltaY: -240 }));
});
await act(async () => Promise.resolve());
expect(onNearHistoryStart).toHaveBeenCalledTimes(2);
});
it("does not force bottom after upward wheel when cached scroll top is stale", async () => {
const scrollTo = vi.fn(function (
this: HTMLElement,
options?: ScrollToOptions | number,
y?: number,
) {
const top = typeof options === "object" ? (options.top ?? 0) : (y ?? 0);
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const historyMounted = Array.from({ length: 20 }, (_, index) => userMessage(index));
const routeBottomAnchorRequest = {
agentId: "agent",
reason: "initial-entry" as const,
requestKey: "server:agent:initial-entry",
};
const renderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted,
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
isAuthoritativeHistoryReady: false,
}),
);
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1491 });
scrollContainer.scrollTop = 0;
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
scrollTo.mockClear();
scrollContainer.scrollTop = 991;
act(() => {
scrollContainer.dispatchEvent(new WheelEvent("wheel", { deltaY: -900 }));
});
scrollContainer.scrollTop = 91;
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
expect(scrollTo).not.toHaveBeenCalled();
scrollContainer.scrollTop = 0;
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
expect(scrollTo).not.toHaveBeenCalled();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 2531 });
act(() => {
root?.render(
strategy.render({
...renderInput,
isAuthoritativeHistoryReady: true,
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
});
it("reattaches follow-output when a small scroll range returns to bottom", async () => {
const scrollTo = vi.fn(function (
this: HTMLElement,
options?: ScrollToOptions | number,
y?: number,
) {
const top = typeof options === "object" ? (options.top ?? 0) : (y ?? 0);
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const renderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1), userMessage(2)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root?.render(
strategy.render({
...renderInput,
isAuthoritativeHistoryReady: true,
}),
);
});
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 550 });
scrollContainer.scrollTop = 50;
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
scrollTo.mockClear();
act(() => {
scrollContainer.dispatchEvent(new WheelEvent("wheel", { deltaY: -30 }));
});
scrollContainer.scrollTop = 20;
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
expect(scrollTo).not.toHaveBeenCalled();
scrollContainer.scrollTop = 50;
act(() => {
scrollContainer.dispatchEvent(new Event("scroll"));
});
scrollTo.mockClear();
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
...renderInput.segments,
liveHead: [userMessage(3)],
},
isAuthoritativeHistoryReady: true,
}),
);
});
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
expect(scrollTo).toHaveBeenCalled();
});
it("keeps following output after geometry, nested-scroll, and zoom wheel events", () => {
const scrollTo = vi.fn(function (this: HTMLElement, options?: ScrollToOptions | number) {
const top = typeof options === "object" ? (options.top ?? 0) : 0;
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const renderInput: StreamRenderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1), userMessage(2)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => root?.render(strategy.render(renderInput)));
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "clientWidth", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "offsetWidth", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1500 });
scrollContainer.scrollTop = 1000;
scrollContainer.getBoundingClientRect = () =>
({
bottom: 500,
height: 500,
left: 0,
right: 500,
top: 0,
width: 500,
x: 0,
y: 0,
toJSON: () => {},
}) as DOMRect;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
const jitterPointerDown = new MouseEvent("pointerdown", {
bubbles: true,
button: 0,
buttons: 1,
clientX: 100,
clientY: 400,
});
const jitterPointerMove = new MouseEvent("pointermove", {
bubbles: true,
buttons: 1,
clientX: 100,
clientY: 397,
});
for (const event of [jitterPointerDown, jitterPointerMove]) {
Object.defineProperties(event, {
isPrimary: { value: true },
pointerId: { value: 1 },
pointerType: { value: "mouse" },
});
}
act(() => {
scrollContainer.dispatchEvent(jitterPointerDown);
window.dispatchEvent(jitterPointerMove);
});
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 700 });
scrollContainer.scrollTop = 800;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
scrollTo.mockClear();
const nestedScroller = document.createElement("div");
nestedScroller.style.overflowY = "auto";
Object.defineProperty(nestedScroller, "clientHeight", { configurable: true, value: 100 });
Object.defineProperty(nestedScroller, "scrollHeight", { configurable: true, value: 300 });
nestedScroller.scrollTop = 100;
scrollContainer.append(nestedScroller);
act(() => {
nestedScroller.dispatchEvent(new WheelEvent("wheel", { bubbles: true, deltaY: -100 }));
scrollContainer.scrollTop = 700;
scrollContainer.dispatchEvent(new Event("scroll"));
scrollContainer.dispatchEvent(
new WheelEvent("wheel", { bubbles: true, ctrlKey: true, deltaY: -100 }),
);
});
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1800 });
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: { ...renderInput.segments, liveHead: [userMessage(3)] },
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(scrollTo).toHaveBeenCalledWith({ top: 1800, behavior: "auto" });
});
it("stops following output after scrollbar and middle-button upward scrolling", () => {
const scrollTo = vi.fn(function (this: HTMLElement, options?: ScrollToOptions | number) {
const top = typeof options === "object" ? (options.top ?? 0) : 0;
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const renderInput: StreamRenderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1), userMessage(2)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef: React.createRef<StreamViewportHandle>(),
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => root?.render(strategy.render(renderInput)));
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "clientWidth", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "offsetWidth", { configurable: true, value: 520 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1500 });
scrollContainer.scrollTop = 1000;
scrollContainer.getBoundingClientRect = () =>
({
bottom: 500,
height: 500,
left: 0,
right: 520,
top: 0,
width: 520,
x: 0,
y: 0,
toJSON: () => {},
}) as DOMRect;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
const scrollbarPointerDown = new MouseEvent("pointerdown", {
bubbles: true,
button: 0,
buttons: 1,
clientX: 515,
clientY: 400,
});
Object.defineProperties(scrollbarPointerDown, {
isPrimary: { value: true },
pointerId: { value: 1 },
pointerType: { value: "mouse" },
});
act(() => scrollContainer.dispatchEvent(scrollbarPointerDown));
scrollContainer.scrollTop = 700;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
scrollTo.mockClear();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1800 });
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: { ...renderInput.segments, liveHead: [userMessage(3)] },
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
scrollContainer.scrollTop = 1300;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
Object.defineProperty(scrollContainer, "offsetWidth", { configurable: true, value: 500 });
scrollContainer.getBoundingClientRect = () =>
({
bottom: 500,
height: 500,
left: 0,
right: 500,
top: 0,
width: 500,
x: 0,
y: 0,
toJSON: () => {},
}) as DOMRect;
const overlayScrollbarPointerDown = new MouseEvent("pointerdown", {
bubbles: true,
button: 0,
buttons: 1,
clientX: 495,
clientY: 400,
});
Object.defineProperties(overlayScrollbarPointerDown, {
isPrimary: { value: true },
pointerId: { value: 2 },
pointerType: { value: "mouse" },
});
act(() => scrollContainer.dispatchEvent(overlayScrollbarPointerDown));
scrollContainer.scrollTop = 900;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
scrollTo.mockClear();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1900 });
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
...renderInput.segments,
liveHead: [userMessage(3), userMessage(4)],
},
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
scrollContainer.scrollTop = 1400;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
const autoscrollPointerDown = new MouseEvent("pointerdown", {
bubbles: true,
button: 1,
buttons: 4,
clientX: 100,
clientY: 400,
});
const autoscrollPointerUp = new MouseEvent("pointerup", {
bubbles: true,
button: 1,
buttons: 0,
clientX: 100,
clientY: 400,
});
const autoscrollPointerMove = new MouseEvent("pointermove", {
bubbles: true,
buttons: 0,
clientX: 100,
clientY: 300,
});
for (const event of [autoscrollPointerDown, autoscrollPointerUp, autoscrollPointerMove]) {
Object.defineProperties(event, {
isPrimary: { value: true },
pointerId: { value: 3 },
pointerType: { value: "mouse" },
});
}
act(() => {
scrollContainer.dispatchEvent(autoscrollPointerDown);
window.dispatchEvent(autoscrollPointerUp);
window.dispatchEvent(autoscrollPointerMove);
});
scrollContainer.scrollTop = 1000;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
scrollTo.mockClear();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 2000 });
act(() => {
root?.render(
strategy.render({
...renderInput,
segments: {
...renderInput.segments,
liveHead: [userMessage(3), userMessage(4), userMessage(5)],
},
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
});
it("keeps the retained viewport mounted while inactive and reconciles it once on return", async () => {
interface ResizeObservation {
callback: ResizeObserverCallback;
disconnect: ReturnType<typeof vi.fn>;
observer: ResizeObserver;
}
const observed = new Map<Element, ResizeObservation>();
Object.defineProperty(globalThis, "ResizeObserver", {
configurable: true,
value: class TestResizeObserver {
readonly disconnect = vi.fn();
constructor(private readonly callback: ResizeObserverCallback) {}
observe(target: Element) {
observed.set(target, {
callback: this.callback,
disconnect: this.disconnect,
observer: this as unknown as ResizeObserver,
});
}
},
});
const notifyResize = (...targets: Element[]) => {
const observation = targets[0] ? observed.get(targets[0]) : undefined;
if (!observation) {
throw new Error("Expected observed resize target");
}
observation.callback(
targets.map(
(target) =>
({
target,
contentRect: target.getBoundingClientRect(),
}) as ResizeObserverEntry,
),
observation.observer,
);
};
const scrollTo = vi.fn(function (this: HTMLElement, options?: ScrollToOptions | number) {
const top = typeof options === "object" ? (options.top ?? 0) : 0;
this.scrollTop = top;
});
HTMLElement.prototype.scrollTo = scrollTo;
const strategy = createWebStreamStrategy({ isMobileBreakpoint: true });
const viewportRef = React.createRef<StreamViewportHandle>();
const onReadingPositionChange = vi.fn();
const renderInput: StreamRenderInput = {
agentId: "agent",
segments: {
historyVirtualized: [],
historyMounted: [userMessage(1), userMessage(2)],
liveHead: [],
},
boundary: {
hasVirtualizedHistory: false,
hasMountedHistory: true,
hasLiveHead: false,
},
renderers: createRenderers(vi.fn()),
listEmptyComponent: null,
viewportRef,
routeBottomAnchorRequest: null,
isAuthoritativeHistoryReady: true,
onNearBottomChange: vi.fn(),
onReadingPositionChange,
onNearHistoryStart: vi.fn().mockReturnValue(true),
isLoadingOlderHistory: false,
hasOlderHistory: false,
olderHistoryProgressKey: null,
scrollEnabled: true,
listStyle: null,
baseListContentContainerStyle: null,
forwardListContentContainerStyle: null,
contentMaxWidth: DEFAULT_CONTENT_MAX_WIDTH,
};
const renderWithActivity = (active: boolean, input: StreamRenderInput = renderInput) => (
<RetainedPanelActivity active={active}>{strategy.render(input)}</RetainedPanelActivity>
);
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => root?.render(renderWithActivity(true)));
const scrollContainer = container.querySelector('[data-testid="agent-chat-scroll"]');
if (!(scrollContainer instanceof HTMLElement)) {
throw new Error("Expected agent chat scroll container");
}
const contentNode = scrollContainer.firstElementChild;
if (!(contentNode instanceof HTMLElement)) {
throw new Error("Expected agent chat content node");
}
const firstRow = contentNode.querySelector('[data-history-row-id="message-1"]');
const secondRow = contentNode.querySelector('[data-history-row-id="message-2"]');
if (!(firstRow instanceof HTMLElement) || !(secondRow instanceof HTMLElement)) {
throw new Error("Expected retained history rows");
}
let rowsShifted = false;
scrollContainer.getBoundingClientRect = () => ({ top: 0, height: 500, bottom: 500 }) as DOMRect;
firstRow.getBoundingClientRect = () =>
({ top: rowsShifted ? -116 : 0, height: 120, bottom: rowsShifted ? 4 : 120 }) as DOMRect;
secondRow.getBoundingClientRect = () =>
({
top: rowsShifted ? 4 : 120,
height: rowsShifted ? 116 : 40,
bottom: rowsShifted ? 120 : 160,
}) as DOMRect;
Object.defineProperty(scrollContainer, "clientHeight", { configurable: true, value: 500 });
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 1500 });
scrollContainer.scrollTop = 1000;
act(() => scrollContainer.dispatchEvent(new Event("scroll")));
const viewportObservation = observed.get(scrollContainer);
expect(viewportObservation).toBeDefined();
act(() => notifyResize(scrollContainer, contentNode));
expect(onReadingPositionChange).toHaveBeenLastCalledWith("message-1");
act(() => root?.render(renderWithActivity(false)));
expect(container.querySelector('[data-testid="agent-chat-scroll"]')).toBe(scrollContainer);
expect(viewportObservation?.disconnect).toHaveBeenCalledOnce();
scrollTo.mockClear();
rowsShifted = true;
act(() => root?.render(renderWithActivity(true)));
act(() => notifyResize(scrollContainer, contentNode));
expect(onReadingPositionChange).toHaveBeenLastCalledWith("message-2");
expect(scrollTo).not.toHaveBeenCalled();
act(() => root?.render(renderWithActivity(false)));
scrollTo.mockClear();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 2200 });
act(() => root?.render(renderWithActivity(true)));
expect(scrollTo).not.toHaveBeenCalled();
act(() => notifyResize(scrollContainer, contentNode));
await act(async () => {
await new Promise((resolve) => requestAnimationFrame(resolve));
});
expect(scrollTo).toHaveBeenCalledWith({ top: 2200, behavior: "auto" });
act(() => root?.render(renderWithActivity(false)));
scrollTo.mockClear();
Object.defineProperty(scrollContainer, "scrollHeight", { configurable: true, value: 2200 });
scrollContainer.scrollTop = 0;
act(() => {
scrollContainer.dispatchEvent(new WheelEvent("wheel", { deltaY: -100 }));
scrollContainer.dispatchEvent(new Event("scroll"));
root?.render(
renderWithActivity(false, {
...renderInput,
segments: { ...renderInput.segments, liveHead: [userMessage(3)] },
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(scrollTo).not.toHaveBeenCalled();
act(() => {
root?.render(
renderWithActivity(true, {
...renderInput,
segments: { ...renderInput.segments, liveHead: [userMessage(3)] },
boundary: { ...renderInput.boundary, hasLiveHead: true },
}),
);
});
expect(container.querySelector('[data-testid="agent-chat-scroll"]')).toBe(scrollContainer);
expect(scrollTo).toHaveBeenCalledWith({ top: 2200, behavior: "auto" });
});
});