Squashed 'third_party/pi/' content from commit d981de122

git-subtree-dir: third_party/pi
git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

packages/agent/test/harness/output-capture.test.ts

@@ -0,0 +1,151 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { BACKGROUND_CONTEXT } from "../../src/harness/context.ts";
+import type { ShellOutputUpdate, ShellOutputView } from "../../src/harness/types.ts";
+import { applyShellOutputUpdate, OutputCapture, sanitizeShellOutput } from "../../src/harness/utils/output-capture.ts";
+
+function createCapture(options?: { maxBytes?: number; maxLines?: number; retain?: "head" | "tail" }) {
+	const updates: ShellOutputUpdate[] = [];
+	const errors: unknown[] = [];
+	const capture = new OutputCapture(
+		{
+			limits: {
+				maxBytes: options?.maxBytes ?? 50,
+				maxLines: options?.maxLines ?? 100,
+				retain: options?.retain ?? "tail",
+			},
+		},
+		BACKGROUND_CONTEXT,
+		{
+			onUpdate: (update) => updates.push(update),
+			onError: (error) => errors.push(error),
+		},
+	);
+	return { capture, updates, errors };
+}
+
+function fold(updates: ShellOutputUpdate[]): ShellOutputView | undefined {
+	let output: ShellOutputView | undefined;
+	for (const update of updates) output = applyShellOutputUpdate(output, update);
+	return output;
+}
+
+afterEach(() => {
+	vi.useRealTimers();
+});
+
+describe("OutputCapture", () => {
+	it("removes invalid control characters without changing text or line boundaries", () => {
+		const input = "a\0b\tc\nd\re\u0007f\ufff9g\ufffbh😀";
+		expect(sanitizeShellOutput(input)).toBe("ab\tc\ndefgh😀");
+		const { capture } = createCapture();
+		capture.push(input);
+		expect(capture.snapshot().text).toBe("ab\tc\ndefgh😀");
+	});
+	it("decodes UTF-8 split across raw process chunks", () => {
+		const { capture } = createCapture();
+		const bytes = new TextEncoder().encode("😀");
+		capture.push(bytes.subarray(0, 2));
+		expect(capture.snapshot().text).toBe("");
+		capture.push(bytes.subarray(2));
+		capture.finish();
+		expect(capture.snapshot().text).toBe("😀");
+	});
+
+	it("publishes the first bounded view immediately and trickling appends responsively", () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(0);
+		const { capture, updates } = createCapture();
+
+		capture.push("one");
+		expect(updates).toHaveLength(1);
+		expect(updates[0]?.kind).toBe("replace");
+
+		vi.advanceTimersByTime(150);
+		capture.push(" two");
+		expect(updates).toHaveLength(2);
+		expect(updates[1]).toMatchObject({ kind: "append", text: " two" });
+		expect(fold(updates)?.text).toBe("one two");
+	});
+
+	it("collapses a burst into one trailing update", () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(0);
+		const { capture, updates } = createCapture();
+		capture.push("a");
+		capture.push("b");
+		capture.push("c");
+		expect(updates).toHaveLength(1);
+
+		vi.advanceTimersByTime(100);
+		expect(updates).toHaveLength(2);
+		expect(updates[1]).toMatchObject({ kind: "append", text: "bc" });
+		expect(fold(updates)?.text).toBe("abc");
+	});
+
+	it("publishes a small slide for post-cap trickle", () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(0);
+		const { capture, updates } = createCapture({ maxBytes: 10 });
+		capture.push("abcdefghij");
+		vi.advanceTimersByTime(150);
+		capture.push("k");
+
+		expect(updates[1]).toMatchObject({ kind: "slide", drop: 1, text: "k" });
+		expect(fold(updates)?.text).toBe("bcdefghijk");
+		expect(fold(updates)?.truncation.totalBytes).toBe(11);
+	});
+
+	it("keeps the exact byte count for a single line larger than its working buffer", () => {
+		vi.useFakeTimers();
+		const { capture } = createCapture({ maxBytes: 10 });
+		capture.push("x".repeat(100));
+		expect(capture.snapshot()).toMatchObject({
+			text: "x".repeat(10),
+			lastLineBytes: 100,
+			truncation: { lastLinePartial: true },
+		});
+	});
+
+	it("uses a cap-bounded replacement after complete turnover", () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(0);
+		const { capture, updates } = createCapture({ maxBytes: 10 });
+		capture.push("abcdefghij");
+		capture.push("x".repeat(100));
+		vi.advanceTimersByTime(100);
+
+		expect(updates[1]?.kind).toBe("replace");
+		expect(fold(updates)?.text).toHaveLength(10);
+		expect(fold(updates)?.truncation.totalBytes).toBe(110);
+	});
+
+	it("forces held state and cancels its trailing timer on dispose", () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(0);
+		const { capture, updates } = createCapture();
+		capture.push("a");
+		capture.push("b");
+		capture.flush();
+		expect(fold(updates)?.text).toBe("ab");
+		capture.dispose();
+		vi.advanceTimersByTime(1_000);
+		expect(updates).toHaveLength(2);
+	});
+
+	it("preserves the original head after its raw guard is crossed", () => {
+		vi.useFakeTimers();
+		const { capture } = createCapture({ maxBytes: 100, maxLines: 2, retain: "head" });
+		capture.push(`first\nsecond\n${"tail".repeat(100)}`);
+		expect(capture.snapshot().text).toBe("first\nsecond");
+	});
+
+	it("publishes spill metadata without resending text", () => {
+		vi.useFakeTimers();
+		const { capture, updates, errors } = createCapture();
+		capture.push("output");
+		capture.setSpillPath("/tmp/output.log");
+		expect(updates.at(-1)).toMatchObject({ kind: "metadata", metadata: { spillPath: "/tmp/output.log" } });
+		expect(fold(updates)?.spillPath).toBe("/tmp/output.log");
+		expect(errors).toEqual([]);
+	});
+});