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+import { TestBed } from '@angular/core/testing';
+import type { DevframeRpcClient } from 'devframe/client';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { ComponentTree } from '../pages/component-tree';
+import {
+  countText,
+  directiveHostLabel,
+  filterAnnouncement,
+  filterTree,
+  withoutDirectiveHosts,
+  type TreeNode,
+} from '../pages/component-tree-state';
+
+function client(pages: Record<string, unknown>) {
+  const calls: { name: string; args: unknown[] }[] = [];
+  const rpc = {
+    call: (name: string, ...args: unknown[]) => {
+      calls.push({ name, args });
+      return Promise.resolve([]);
+    },
+    callEvent: () => Promise.resolve(),
+    sharedState: (name: string) =>
+      Promise.resolve({
+        value: () => (name === 'component-tree' ? { pages } : null),
+        on: () => () => {},
+      }),
+  };
+  return {
+    calls,
+    client: { connectionMeta: {}, scope: () => ({ rpc }) } as unknown as DevframeRpcClient,
+  };
+}
+
+const roots: TreeNode[] = [
+  {
+    id: 'c1',
+    name: 'App',
+    tag: 'app-root',
+    hydration: 'hydrated',
+    children: [
+      {
+        id: 'c2',
+        name: 'RouterLink',
+        tag: 'a',
+        kind: 'directive',
+        directives: ['RouterLink'],
+        attributes: ['routerLink'],
+        children: [
+          { id: 'c3', name: 'Badge', tag: 'app-badge', hydration: 'hydrated', children: [] },
+        ],
+      },
+      {
+        id: 'c4',
+        name: 'TripMap',
+        tag: 'app-map',
+        hydration: 'skipped',
+        children: [
+          {
+            id: 'c5',
+            name: 'MatTooltip',
+            tag: 'button',
+            kind: 'directive',
+            directives: ['MatTooltip'],
+            attributes: ['matTooltip'],
+            children: [],
+          },
+        ],
+      },
+      { id: 'c6', name: 'Price', tag: 'app-price', hydration: 'mismatched', children: [] },
+    ],
+  },
+];
+
+const hydration = {
+  hydrated: true,
+  counts: { hydrated: 2, skipped: 1, mismatched: 1, client: 0, dehydratedBlocks: 1 },
+  mismatches: [{ id: 'c6', name: 'Price', tag: 'app-price', expected: '<div>', actual: '<span>' }],
+};
+
+const page = (extra: Record<string, unknown> = {}) => ({
+  pageId: 'p1',
+  roots,
+  count: 4,
+  directiveHostCount: 2,
+  detail: null,
+  reportedAt: 1000,
+  hydration,
+  ...extra,
+});
+
+async function render(value: unknown) {
+  const fixture = TestBed.createComponent(ComponentTree);
+  const rpc = client({ p1: value });
+  fixture.componentRef.setInput('rpc', rpc.client);
+  for (let i = 0; i < 3; i++) {
+    await new Promise((resolve) => setTimeout(resolve));
+    await fixture.whenStable();
+  }
+  const el = fixture.nativeElement as HTMLElement;
+  const settle = async () => {
+    fixture.detectChanges();
+    await fixture.whenStable();
+  };
+  return { fixture, el, calls: rpc.calls, settle };
+}
+
+const rowIds = (el: HTMLElement) =>
+  Array.from(el.querySelectorAll<HTMLElement>('.row')).map((row) => row.dataset['id']);
+
+describe('tree search and directive hosts (state)', () => {
+  it('filters with tag, directive and text tokens, keeping ancestors', () => {
+    const { nodes, matches } = filterTree(roots, '<button> [matTooltip]');
+    expect(matches).toBe(1);
+    expect(nodes[0].children.map((n) => n.id)).toEqual(['c4']);
+    expect(nodes[0].children[0].children.map((n) => n.id)).toEqual(['c5']);
+    expect(filterTree(roots, '<app-map>').matches).toBe(1);
+    expect(filterTree(roots, '[routerLink] badge').matches).toBe(0);
+    expect(filterTree(roots, 'price').matches).toBe(1);
+  });
+
+  it('lifts the children of hidden directive hosts to their parent', () => {
+    const shown = withoutDirectiveHosts(roots);
+    expect(shown[0].children.map((n) => n.id)).toEqual(['c3', 'c4', 'c6']);
+    expect(shown[0].children[1].children).toEqual([]);
+  });
+
+  it('labels a directive host by its attributes, else its classes, and counts hosts apart', () => {
+    expect(directiveHostLabel(roots[0].children[0])).toBe('[routerLink]');
+    expect(
+      directiveHostLabel({
+        id: 'x',
+        name: 'Foo',
+        tag: 'div',
+        directives: ['Highlight'],
+        children: [],
+      }),
+    ).toBe('[Highlight]');
+    expect(countText(4, 0, false, false, 2)).toBe('4 instances · 2 directive hosts');
+    expect(countText(4, 1, true, false, 2)).toBe('1 of 6');
+    // With directive hosts shown, the filter result counts rows, not instances.
+    expect(filterAnnouncement(4, 1, 'tip', false, 2)).toBe('1 of 6 rows match.');
+    expect(filterAnnouncement(4, 1, 'tip')).toBe('1 of 4 instances match.');
+  });
+});
+
+describe('component tree hydration and directive hosts', () => {
+  beforeEach(() => {
+    vi.stubGlobal('CSS', { escape: (value: string) => value });
+    Element.prototype.scrollIntoView ??= () => {};
+    try {
+      localStorage.clear();
+    } catch {
+      // no storage in this environment
+    }
+  });
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    document.body.innerHTML = '';
+  });
+
+  it('shows a hydration badge with text on each component row', async () => {
+    const { el } = await render(page());
+    const badges = Array.from(el.querySelectorAll('.row .hyd')).map((b) =>
+      b.textContent!.replace(/\s+/g, ' ').trim(),
+    );
+    expect(badges).toEqual([
+      'Hydration: Hydrated',
+      'Hydration: Hydrated',
+      'Hydration: Skipped',
+      'Hydration: Mismatch',
+    ]);
+    expect(el.querySelector('.hyd-mismatched')).not.toBeNull();
+  });
+
+  it('shows directive hosts as their own rows, hidden by the toolbar toggle', async () => {
+    const { el, settle } = await render(page());
+    const host = el.querySelector('.row[data-id="c2"]')!;
+    expect(host.querySelector('.host-tag')!.textContent).toBe('<a>');
+    expect(host.querySelector('.host-dirs')!.textContent!.trim()).toBe('[routerLink]');
+    expect(host.querySelector('.sr-only')!.textContent).toBe('directive host');
+    expect(el.querySelectorAll('.row.dir-host')).toHaveLength(2);
+    expect(el.querySelector('.count')!.textContent).toContain('4 instances · 2 directive hosts');
+
+    const toggle = Array.from(el.querySelectorAll<HTMLButtonElement>('.tree-action')).find((b) =>
+      b.textContent!.includes('Directive hosts'),
+    )!;
+    expect(toggle.getAttribute('aria-pressed')).toBe('true');
+    toggle.click();
+    await settle();
+    expect(toggle.getAttribute('aria-pressed')).toBe('false');
+    expect(el.querySelectorAll('.row.dir-host')).toHaveLength(0);
+    expect(rowIds(el)).toEqual(['c1', 'c3', 'c4', 'c6']);
+    expect(localStorage.getItem('pangular:components:directive-hosts')).toBe('hidden');
+  });
+
+  it('filters the tree with the search syntax', async () => {
+    const { el, fixture, settle } = await render(page());
+    fixture.componentInstance.setFilter('<button> [matTooltip]');
+    await settle();
+    expect(rowIds(el)).toEqual(['c1', 'c4', 'c5']);
+    expect(el.querySelector('.count')!.textContent!.trim()).toBe('1 of 6');
+    expect(fixture.componentInstance.announcement()).toBe('1 of 6 rows match.');
+  });
+
+  it('selects a directive host locally and offers its owning component', async () => {
+    const { el, calls, settle } = await render(page());
+    const row = el.querySelector<HTMLElement>('.row[data-id="c5"]')!;
+    row.click();
+    await settle();
+    expect(calls.some((c) => c.name === 'select-component')).toBe(false);
+    const detail = el.querySelector('.detail')!;
+    expect(detail.querySelector('.badge')!.textContent).toBe('directive host');
+    expect(detail.textContent).toContain('MatTooltip');
+    const owner = detail.querySelector<HTMLButtonElement>('.owner-action button')!;
+    expect(owner.textContent!.trim()).toBe('Show TripMap');
+    owner.focus();
+    owner.click();
+    await settle();
+    expect(el.querySelector('.row.selected')!.getAttribute('data-id')).toBe('c4');
+    // The button goes away with the host's detail, so focus moves to the owner's row.
+    expect(document.activeElement).not.toBe(document.body);
+    expect(document.activeElement?.getAttribute('data-id')).toBe('c4');
+    expect(document.activeElement?.getAttribute('tabindex')).toBe('0');
+  });
+
+  it('reaches directive host rows with the arrow keys', async () => {
+    const { el, settle } = await render(page());
+    const tree = el.querySelector<HTMLElement>('[role="tree"]')!;
+    el.querySelector<HTMLElement>('.row[data-id="c1"]')!.focus();
+    tree.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
+    await new Promise((resolve) => queueMicrotask(() => resolve(null)));
+    await settle();
+    expect(document.activeElement?.getAttribute('data-id')).toBe('c2');
+    expect(document.activeElement?.getAttribute('role')).toBe('treeitem');
+  });
+
+  it('summarizes hydration and asks the page to outline it', async () => {
+    const { el, calls, settle } = await render(page());
+    const section = el.querySelector('app-hydration-section')!;
+    const counts = Array.from(section.querySelectorAll('.counts li')).map((li) =>
+      li.textContent!.replace(/\s+/g, ' ').trim(),
+    );
+    expect(counts).toEqual([
+      '2 hydrated',
+      '1 skipped',
+      '1 mismatched',
+      '0 created on the client',
+      '1 dehydrated @defer block',
+    ]);
+    expect(section.textContent).toContain('Expected <div>');
+    const outline = section.querySelector<HTMLButtonElement>('.outline')!;
+    expect(outline.getAttribute('aria-pressed')).toBe('false');
+    outline.click();
+    await settle();
+    expect(outline.getAttribute('aria-pressed')).toBe('true');
+    const call = calls.find((c) => c.name === 'request-hydration-overlay')!;
+    expect(call.args[0]).toEqual({ pageId: 'p1', on: true });
+
+    section.querySelector<HTMLButtonElement>('.mismatch')!.click();
+    await settle();
+    expect(el.querySelector('.row.selected')!.getAttribute('data-id')).toBe('c6');
+  });
+
+  it('says hydration does not apply to a page rendered in the browser only', async () => {
+    const plain = (nodes: TreeNode[]): TreeNode[] =>
+      nodes.map(({ hydration: _, ...node }) => ({ ...node, children: plain(node.children) }));
+    const { el } = await render(page({ hydration: undefined, roots: plain(roots) }));
+    const section = el.querySelector('app-hydration-section')!;
+    expect(section.textContent).toContain('not rendered on the server');
+    expect(section.querySelector('.outline')).toBeNull();
+    expect(el.querySelector('.row .hyd')).toBeNull();
+  });
+
+  it('says client hydration is off when the server HTML was not hydrated', async () => {
+    const { el } = await render(page({ hydration: { ...hydration, hydrated: false } }));
+    expect(el.querySelector('app-hydration-section')!.textContent).toContain(
+      'no component was hydrated',
+    );
+  });
+});