fix(junit): preserve suite identity for hook failures reported from workers

lib/mocha/hooks.js

@@ -33,12 +33,22 @@ class Hook {
   }
 
   simplify() {
+    // this.runnable (context.ctx.test) is the hook's own runnable; its
+    // .parent is the real Mocha Suite that owns this hook. Included here so
+    // run-workers can forward suite identity to the main process, where
+    // listeners (e.g. junitReporter) have no other way to recover it — the
+    // worker's live Suite/ctx objects aren't serializable across the thread
+    // boundary, only these plain fields are.
+    const suite = this.runnable?.parent
     return {
       hookName: this.hookName,
       title: this.title,
       // test: this.test ? serializeTest(this.test) : null,
       // suite: this.suite ? serializeSuite(this.suite) : null,
       error: this.err ? serializeError(this.err) : null,
+      suiteTitle: suite?.title || null,
+      suiteFile: suite?.file || null,
+      suiteTags: suite?.tags || [],
     }
   }
 

lib/plugin/junitReporter.js

@@ -67,13 +67,29 @@ export default function (config = {}) {
 
   let written = false
   const hookFailures = []
+  // groupBySuite() (below) groups by object identity, not by value — reused
+  // across BeforeSuite/AfterSuite failures from the same worker-forwarded
+  // suite so they land in one <testsuite>, not one per failure.
+  const workerSuiteByKey = new Map()
 
   event.dispatcher.on(event.hook.failed, hook => {
     if (!hook || !['BeforeSuite', 'AfterSuite'].includes(hook.hookName)) return
     const err = hook.err || hook.error
     if (!err) return
     const runnable = hook.ctx && hook.ctx.test
-    const suite = runnable && runnable.parent
+    // Under run-workers, hook.ctx is absent — the failure arrives as the
+    // plain object from Hook.simplify() in the main process instead of a
+    // live Hook instance. Fall back to the suiteTitle/suiteFile/suiteTags
+    // simplify() carries across the worker boundary so the failure still
+    // groups under its real suite instead of the "Tests" fallback.
+    let suite = runnable && runnable.parent
+    if (!suite && hook.suiteTitle) {
+      const key = `${hook.suiteTitle} ${hook.suiteFile || ''}`
+      if (!workerSuiteByKey.has(key)) {
+        workerSuiteByKey.set(key, { title: hook.suiteTitle, file: hook.suiteFile, tags: hook.suiteTags })
+      }
+      suite = workerSuiteByKey.get(key)
+    }
     hookFailures.push({
       title: hook.title || `${hook.hookName} hook failed`,
       state: 'failed',