From 7c7ea141f01edfd9e6e0b603c6f4b7bc37c51c92 Mon Sep 17 00:00:00 2001
From: Jeremy Rose <jeremya@chromium.org>
Date: Thu, 11 Jun 2020 11:35:50 -0700
Subject: [PATCH] test: extract defer helper (#24019)

---
 spec-main/index.js        | 18 ++++++++++++++----
 spec-main/spec-helpers.ts |  2 +-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/spec-main/index.js b/spec-main/index.js
index a90a35a5aa3e..92c0d18d5ddf 100644
--- a/spec-main/index.js
+++ b/spec-main/index.js
@@ -60,6 +60,20 @@ app.whenReady().then(async () => {
   }
   const mocha = new Mocha(mochaOptions);
 
+  // The cleanup method is registered this way rather than through an
+  // `afterEach` at the top level so that it can run before other `afterEach`
+  // methods.
+  //
+  // The order of events is:
+  // 1. test completes,
+  // 2. `defer()`-ed methods run, in reverse order,
+  // 3. regular `afterEach` hooks run.
+  const { runCleanupFunctions } = require('./spec-helpers');
+  mocha.suite.on('suite', function attach (suite) {
+    suite.afterEach('cleanup', runCleanupFunctions);
+    suite.on('suite', attach);
+  });
+
   if (!process.env.MOCHA_REPORTER) {
     mocha.ui('bdd').reporter('tap');
   }
@@ -110,8 +124,4 @@ app.whenReady().then(async () => {
   chai.use(require('dirty-chai'));
 
   const runner = mocha.run(cb);
-  const { runCleanupFunctions } = require('./spec-helpers');
-  runner.on('test end', () => {
-    runCleanupFunctions();
-  });
 });
diff --git a/spec-main/spec-helpers.ts b/spec-main/spec-helpers.ts
index 1bf85622db9f..ca1a5e78f65c 100644
--- a/spec-main/spec-helpers.ts
+++ b/spec-main/spec-helpers.ts
@@ -19,7 +19,7 @@ export async function runCleanupFunctions () {
 }
 
 export function defer (f: CleanupFunction) {
-  cleanupFunctions.push(f);
+  cleanupFunctions.unshift(f);
 }
 
 class RemoteControlApp {