test: make hard-coded caps overridable behind seams (#1781 B5)

packages/capture-kit/src/durable-json.test.ts

@@ -12,6 +12,23 @@ test('bounded durable JSON rejects cycles and excessive depth', () => {
   assert.equal(isBoundedJsonObject(nested), false);
 });
 
+test('bounded durable JSON accepts exactly the node cap and rejects one node past it', () => {
+  // Every node counts: the root object, the `items` array, and each leaf. The
+  // cap is 4,096 nodes, so 4,094 leaves sit exactly on it and 4,095 leaves are
+  // the first document over. Depth stays at 2, so only the node budget can
+  // decide either case, and the leaf kind selects which of the two counting
+  // sites owns the rejection.
+  const objectLeaves = (count: number) => ({ items: Array.from({ length: count }, () => ({})) });
+  assert.equal(isBoundedJsonObject(objectLeaves(4_094)), true);
+  assert.equal(isBoundedJsonObject(objectLeaves(4_095)), false);
+
+  const arrayLeaves = (count: number) => ({
+    items: Array.from({ length: count }, () => [] as never[]),
+  });
+  assert.equal(isBoundedJsonObject(arrayLeaves(4_094)), true);
+  assert.equal(isBoundedJsonObject(arrayLeaves(4_095)), false);
+});
+
 test('validated durable JSON freezes without recursively revalidating every subtree', () => {
   let reads = 0;
   const leaf = Object.defineProperty({}, 'value', {

src/platforms/harmonyos/__tests__/snapshot.test.ts

@@ -1,6 +1,42 @@
 import assert from 'node:assert/strict';
-import { test } from 'vitest';
-import { parseArkUiBounds, parseHarmonyLayout } from '../snapshot.ts';
+import fs from 'node:fs';
+import { beforeEach, test, vi } from 'vitest';
+
+const { runHarmonyHdc } = vi.hoisted(() => ({ runHarmonyHdc: vi.fn() }));
+
+vi.mock('../hdc.ts', () => ({ runHarmonyHdc }));
+
+import {
+  collectArkUiNodes,
+  parseArkUiBounds,
+  parseHarmonyLayout,
+  snapshotHarmony,
+} from '../snapshot.ts';
+
+const DEVICE = {
+  platform: 'harmonyos' as const,
+  id: 'harmony-1',
+  name: 'HarmonyOS test device',
+  kind: 'device' as const,
+  target: 'mobile' as const,
+  booted: true,
+};
+
+const UNBOUNDED = { maxDepth: Number.POSITIVE_INFINITY, interactiveOnly: false };
+
+beforeEach(() => {
+  runHarmonyHdc.mockReset();
+});
+
+/** Scripts `uitest dumpLayout` + `file recv` so the pulled layout is `layout`. */
+function scriptHarmonyLayoutDump(layout: unknown): void {
+  runHarmonyHdc.mockImplementation(async (_device: unknown, args: string[]) => {
+    if (args[0] === 'file' && args[1] === 'recv') {
+      fs.writeFileSync(args[3] as string, JSON.stringify(layout), 'utf8');
+    }
+    return { exitCode: 0, stdout: '', stderr: '' };
+  });
+}
 
 test('parseArkUiBounds converts API 24 layout bounds into a rectangle', () => {
   assert.deepEqual(parseArkUiBounds('[84,1127][1172,1295]'), {
@@ -15,3 +51,76 @@ test('parseArkUiBounds converts API 24 layout bounds into a rectangle', () => {
 test('parseHarmonyLayout rejects non-object uitest documents', () => {
   assert.throws(() => parseHarmonyLayout('[]'), /invalid layout JSON/i);
 });
+
+test('collectArkUiNodes reports truncation once the emitted-node limit is reached', () => {
+  const root = parseHarmonyLayout(
+    JSON.stringify({
+      attributes: { type: 'root', bounds: '[0,0][1080,2340]' },
+      children: [
+        { attributes: { type: 'Button', text: 'first', clickable: 'true' } },
+        { attributes: { type: 'Button', text: 'second', clickable: 'true' } },
+        { attributes: { type: 'Button', text: 'third', clickable: 'true' } },
+      ],
+    }),
+  );
+
+  const capped = collectArkUiNodes(root, { ...UNBOUNDED, maxNodes: 2 });
+  assert.equal(capped.truncated, true);
+  assert.deepEqual(
+    capped.nodes.map((node) => node.value ?? node.type),
+    ['Application', 'first'],
+  );
+  assert.deepEqual(capped.analysis, { rawNodeCount: 4, maxDepth: 1 });
+
+  const uncapped = collectArkUiNodes(root, { ...UNBOUNDED, maxNodes: 5_000 });
+  assert.equal(uncapped.truncated, false);
+  assert.equal(uncapped.nodes.length, 4);
+});
+
+test('collectArkUiNodes keeps counting the tree below a node the limit omitted', () => {
+  // The limit fills on `first`, so `branch` and everything under it is
+  // omitted. `analysis` still describes the tree the device reported, so the
+  // omitted subtree must reach both counters: five nodes, deepest at depth 3.
+  const root = parseHarmonyLayout(
+    JSON.stringify({
+      attributes: { type: 'root', bounds: '[0,0][1080,2340]' },
+      children: [
+        { attributes: { type: 'Button', text: 'first', clickable: 'true' } },
+        {
+          attributes: { type: 'Column', text: 'branch' },
+          children: [
+            {
+              attributes: { type: 'Row', text: 'leaf' },
+              children: [{ attributes: { type: 'Text', text: 'deep' } }],
+            },
+          ],
+        },
+      ],
+    }),
+  );
+
+  const capped = collectArkUiNodes(root, { ...UNBOUNDED, maxNodes: 2 });
+
+  assert.equal(capped.truncated, true);
+  assert.deepEqual(
+    capped.nodes.map((node) => node.value ?? node.type),
+    ['Application', 'first'],
+  );
+  assert.deepEqual(capped.analysis, { rawNodeCount: 5, maxDepth: 3 });
+});
+
+test('snapshotHarmony pulls a uitest layout and reports its analysis', async () => {
+  scriptHarmonyLayoutDump({
+    attributes: { type: 'root', bounds: '[0,0][1080,2340]' },
+    children: [{ attributes: { type: 'Button', text: 'first', clickable: 'true' } }],
+  });
+
+  const snapshot = await snapshotHarmony(DEVICE);
+
+  assert.equal(snapshot.truncated, undefined);
+  assert.deepEqual(
+    snapshot.nodes.map((node) => node.value ?? node.type),
+    ['Application', 'first'],
+  );
+  assert.deepEqual(snapshot.analysis, { rawNodeCount: 2, maxDepth: 1 });
+});

src/platforms/harmonyos/snapshot.ts

@@ -80,33 +80,55 @@ function buildHarmonySnapshot(
   nodes: RawSnapshotNode[];
   truncated?: boolean;
   analysis: { rawNodeCount: number; maxDepth: number };
+} {
+  const { nodes, truncated, analysis } = collectArkUiNodes(root, {
+    maxNodes: MAX_NODES,
+    maxDepth: options.depth ?? Number.POSITIVE_INFINITY,
+    interactiveOnly: options.interactiveOnly === true,
+  });
+  return { nodes, ...(truncated ? { truncated: true } : {}), analysis };
+}
+
+/**
+ * Traversal and emission policy for an ArkUI layout tree, with every bound
+ * passed in.
+ *
+ * Emission and accounting are deliberately separate: emission stops at
+ * `maxNodes`, while `analysis` keeps describing the tree the device reported,
+ * so the walk continues counting and descending below an omitted node. Halting
+ * there would under-report `rawNodeCount` and `maxDepth` for exactly the
+ * oversized trees the cap exists for.
+ */
+export function collectArkUiNodes(
+  root: ArkUiLayoutNode,
+  policy: { maxNodes: number; maxDepth: number; interactiveOnly: boolean },
+): {
+  nodes: RawSnapshotNode[];
+  truncated: boolean;
+  analysis: { rawNodeCount: number; maxDepth: number };
 } {
   const nodes: RawSnapshotNode[] = [];
   let rawNodeCount = 0;
   let maxDepth = 0;
   let truncated = false;
-  const maxNodes = MAX_NODES;
   const walk = (node: ArkUiLayoutNode, depth: number, parentIndex?: number): void => {
     rawNodeCount += 1;
     maxDepth = Math.max(maxDepth, depth);
-    if (nodes.length >= maxNodes) {
+    let currentIndex = parentIndex;
+    if (nodes.length >= policy.maxNodes) {
       truncated = true;
-      return;
+    } else {
+      const attributes = node.attributes ?? {};
+      const candidate = arkUiNodeFromAttributes(attributes, nodes.length, depth, parentIndex);
+      const include = !policy.interactiveOnly || candidate.hittable === true;
+      currentIndex = include ? nodes.push(candidate) - 1 : parentIndex;
     }
-    const attributes = node.attributes ?? {};
-    const candidate = arkUiNodeFromAttributes(attributes, nodes.length, depth, parentIndex);
-    const include = !options.interactiveOnly || candidate.hittable === true;
-    const currentIndex = include ? nodes.push(candidate) - 1 : parentIndex;
-    if (depth < (options.depth ?? Number.POSITIVE_INFINITY)) {
+    if (depth < policy.maxDepth) {
       for (const child of node.children ?? []) walk(child, depth + 1, currentIndex);
     }
   };
   walk(root, 0);
-  return {
-    nodes,
-    ...(truncated ? { truncated: true } : {}),
-    analysis: { rawNodeCount, maxDepth },
-  };
+  return { nodes, truncated, analysis: { rawNodeCount, maxDepth } };
 }
 
 function arkUiNodeFromAttributes(