test_runner: wait for reporter and parser to finish

lib/internal/test_runner/runner.js

@@ -13,6 +13,7 @@ const {
   ObjectAssign,
   ObjectKeys,
   PromisePrototypeThen,
+  SafePromiseAll,
   SafePromiseAllReturnVoid,
   SafePromiseAllSettledReturnVoid,
   SafeMap,
@@ -24,6 +25,7 @@ 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');
@@ -299,7 +301,10 @@ 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);

lib/internal/test_runner/test.js

@@ -50,6 +50,7 @@ const {
   validateUint32,
 } = require('internal/validators');
 const { setTimeout } = require('timers/promises');
+const { setInterval, clearInterval } = require('timers');
 const { TIMEOUT_MAX } = require('internal/timers');
 const { availableParallelism } = require('os');
 const { bigint: hrtime } = process.hrtime;
@@ -649,6 +650,10 @@ class Test extends AsyncResource {
         this.reporter.coverage(this.nesting, kFilename, this.coverage);
       }
 
+      // In case the event loop has ended and reporter has not drained,
+      // we use a timer to keep the process alive until the reporter is done.
+      const handle = setInterval(() => {}, TIMEOUT_MAX);
+      this.reporter.once('close', () => clearInterval(handle));
       this.reporter.push(null);
     }
   }