[cypress] Log timestamp for each line of integration test output

packages/cypress-plugin/test/integration/src/run-test-case.ts

@@ -888,7 +888,7 @@ export const runTestCase = async (
 
  const onOutput = (
  name: string,
- onLine: (line: string) => void,
+ onLine: (line: string, now: Date) => void,
  escapeDebugOutput: boolean
  ): ((data: Buffer) => void) => {
  const debugExt = debug.extend(name);
@@ -899,12 +899,13 @@ export const runTestCase = async (
  // Don't eat the last line of output.
  cypressChild.on("exit", () => {
  if (pending.s !== "") {
- onLine(pending.s);
+ onLine(pending.s, new Date());
  debugExt(escapeDebugOutput ? JSON.stringify(pending.s) : pending.s);
  }
  });
 
  return (data: Buffer): void => {
+ const now = new Date();
  // In case data terminates in the middle of a Unicode sequence, we need to use a stateful
  // TextDecoder with `stream: true`. Otherwise, invalid UTF-8 sequences at the end get
  // converted to 0xFFFD, which breaks the tests non-deterministically (i.e., makes them flaky).
@@ -914,7 +915,7 @@ export const runTestCase = async (
  // partial line that we want to defer until the next call.
  lines.slice(0, lines.length - 1).forEach((line, idx) => {
  const lineWithPending = idx === 0 ? pending.s + line : line;
- onLine(lineWithPending);
+ onLine(lineWithPending, now);
  debugExt(
  escapeDebugOutput ? JSON.stringify(lineWithPending) : lineWithPending
  );
@@ -931,7 +932,9 @@ export const runTestCase = async (
  "data",
  onOutput(
  "stderr",
- combinedLines.push.bind(combinedLines),
+ (line, now) => {
+ combinedLines.push(`${now.toISOString()} ${line}`);
+ },
  // Don't escape stderr output since it likely comes from debug output in the subprocess, which
  // is intended for human consumption and not for verifying test results.
  false
@@ -941,9 +944,9 @@ export const runTestCase = async (
  "data",
  onOutput(
  "stdout",
- (line) => {
+ (line, now) => {
  stdoutLines.push(line);
- combinedLines.push(line);
+ combinedLines.push(`${now.toISOString()} ${line}`);
  },
  // Escape special characters in debug output so that we can more easily understand test
  // failures related to unexpected output.