test_runner: bootstrap reporters before running tests

doc/api/test.md

@@ -684,6 +684,9 @@ added:
     **Default:** `false`.
   * `files`: {Array} An array containing the list of files to run.
     **Default** matching files from [test runner execution model][].
+  * `setup` {Function} A function that accepts the `TestsStream` instance
+    and can be used to setup listeners before any tests are run.
+    **Default:** `undefined`.
   * `signal` {AbortSignal} Allows aborting an in-progress test execution.
   * `timeout` {number} A number of milliseconds the test execution will
     fail after.

lib/internal/main/test_runner.js

@@ -22,8 +22,7 @@ if (isUsingInspector()) {
   inspectPort = process.debugPort;
 }
 
-const testsStream = run({ concurrency, inspectPort, watch: getOptionValue('--watch') });
-testsStream.once('test:fail', () => {
+run({ concurrency, inspectPort, watch: getOptionValue('--watch'), setup: setupTestReporters })
+.once('test:fail', () => {
   process.exitCode = kGenericUserError;
 });
-setupTestReporters(testsStream);

lib/internal/test_runner/harness.js

@@ -161,29 +161,35 @@ function setup(root) {
 }
 
 let globalRoot;
+let reportersSetup;
 function getGlobalRoot() {
   if (!globalRoot) {
     globalRoot = createTestTree();
     globalRoot.reporter.once('test:fail', () => {
       process.exitCode = kGenericUserError;
     });
-    setupTestReporters(globalRoot.reporter);
+    reportersSetup = setupTestReporters(globalRoot.reporter);
   }
   return globalRoot;
 }
 
+async function startSubtest(subtest) {
+  await reportersSetup;
+  await subtest.start();
+}
+
 function test(name, options, fn) {
   const parent = testResources.get(executionAsyncId()) || getGlobalRoot();
   const subtest = parent.createSubtest(Test, name, options, fn);
-  return subtest.start();
+  return startSubtest(subtest);
 }
 
 function runInParentContext(Factory) {
   function run(name, options, fn, overrides) {
     const parent = testResources.get(executionAsyncId()) || getGlobalRoot();
     const subtest = parent.createSubtest(Factory, name, options, fn, overrides);
     if (parent === getGlobalRoot()) {
-      subtest.start();
+      startSubtest(subtest);
     }
   }
 

lib/internal/test_runner/runner.js

@@ -13,8 +13,10 @@ const {
   ObjectAssign,
   ObjectKeys,
   PromisePrototypeThen,
+  SafePromiseAll,
   SafePromiseAllReturnVoid,
   SafePromiseAllSettledReturnVoid,
+  PromiseResolve,
   SafeMap,
   SafeSet,
   StringPrototypeIndexOf,
@@ -24,6 +26,7 @@ const {
 
 const { spawn } = require('child_process');
 const { readdirSync, statSync } = require('fs');
+const { finished } = require('internal/streams/end-of-stream');
 // TODO(aduh95): switch to internal/readline/interface when backporting to Node.js 16.x is no longer a concern.
 const { createInterface } = require('readline');
 const { FilesWatcher } = require('internal/watch_mode/files_watcher');
@@ -33,7 +36,7 @@ const {
     ERR_TEST_FAILURE,
   },
 } = require('internal/errors');
-const { validateArray, validateBoolean } = require('internal/validators');
+const { validateArray, validateBoolean, validateFunction } = require('internal/validators');
 const { getInspectPort, isUsingInspector, isInspectorMessage } = require('internal/util/inspector');
 const { kEmptyObject } = require('internal/util');
 const { createTestTree } = require('internal/test_runner/harness');
@@ -299,7 +302,10 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
       subtest.addToReport(ast);
     });
 
-    const { 0: code, 1: signal } = await once(child, 'exit', { signal: t.signal });
+    const { 0: { 0: code, 1: signal } } = await SafePromiseAll([
+      once(child, 'exit', { signal: t.signal }),
+      finished(parser, { signal: t.signal }),
+    ]);
 
     runningProcesses.delete(path);
     runningSubtests.delete(path);
@@ -348,14 +354,17 @@ function run(options) {
   if (options === null || typeof options !== 'object') {
     options = kEmptyObject;
   }
-  const { concurrency, timeout, signal, files, inspectPort, watch } = options;
+  const { concurrency, timeout, signal, files, inspectPort, watch, setup } = options;
 
   if (files != null) {
     validateArray(files, 'options.files');
   }
   if (watch != null) {
     validateBoolean(watch, 'options.watch');
   }
+  if (setup != null) {
+    validateFunction(setup, 'options.setup');
+  }
 
   const root = createTestTree({ concurrency, timeout, signal });
   const testFiles = files ?? createTestFileList();
@@ -366,13 +375,13 @@ function run(options) {
     filesWatcher = watchFiles(testFiles, root, inspectPort);
     postRun = undefined;
   }
-
-  PromisePrototypeThen(SafePromiseAllSettledReturnVoid(testFiles, (path) => {
+  const runFiles = () => SafePromiseAllSettledReturnVoid(testFiles, (path) => {
     const subtest = runTestFile(path, root, inspectPort, filesWatcher);
     runningSubtests.set(path, subtest);
     return subtest;
-  }), postRun);
+  });
 
+  PromisePrototypeThen(PromisePrototypeThen(PromiseResolve(setup?.(root.reporter)), runFiles), postRun);
 
   return root.reporter;
 }