From 629a7f112583c2667f81f5c9aba5afc2a31a8be2 Mon Sep 17 00:00:00 2001
From: "Benjamin E. Coe" <bencoe@google.com>
Date: Fri, 3 Apr 2020 08:53:06 -0700
Subject: [PATCH] refactor(test): use exponential backoff and retry some
 integration tests (#402)

* refactor(test): use exponential backoff and retry for integration tests

* chore: remove p-retry dependency, in favor of this.retries

* chore: slight tweak to retry logic

* chore: add stagger as suggested
---
 .../samples/package.json                      |  1 -
 .../samples/test/quickstart.test.js           | 34 ++++++++++---------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/packages/google-cloud-monitoring/samples/package.json b/packages/google-cloud-monitoring/samples/package.json
index 147004e47b7..4698ed8fc0d 100644
--- a/packages/google-cloud-monitoring/samples/package.json
+++ b/packages/google-cloud-monitoring/samples/package.json
@@ -20,7 +20,6 @@
   "devDependencies": {
     "chai": "^4.2.0",
     "mocha": "^7.0.0",
-    "p-retry": "^4.0.0",
     "uuid": "^7.0.0"
   }
 }
diff --git a/packages/google-cloud-monitoring/samples/test/quickstart.test.js b/packages/google-cloud-monitoring/samples/test/quickstart.test.js
index 50bbdde1616..82bee1637c7 100644
--- a/packages/google-cloud-monitoring/samples/test/quickstart.test.js
+++ b/packages/google-cloud-monitoring/samples/test/quickstart.test.js
@@ -17,24 +17,26 @@
 const {assert} = require('chai');
 const {describe, it} = require('mocha');
 const cp = require('child_process');
-const retry = require('p-retry');
 
 const execSync = cmd => cp.execSync(cmd, {encoding: 'utf-8'});
-
+// A helper for delaying integration tests with an exponential backoff.
+// See examples like: https://github.com/googleapis/nodejs-monitoring/issues/190,
+// https://github.com/googleapis/nodejs-monitoring/issues/191.
+const delay = async test => {
+  const retries = test.currentRetry();
+  if (retries === 0) return; // no retry on the first failure.
+  // see: https://cloud.google.com/storage/docs/exponential-backoff:
+  const ms = Math.pow(2, retries) * 250 + Math.random() * 1000;
+  return new Promise(done => {
+    console.info(`retrying "${test.title}" in ${ms}ms`);
+    setTimeout(done, ms);
+  });
+};
 describe('quickstart', () => {
-  it('should run the quickstart', async () => {
-    // The write in the quickstart appears to be very, very flaky.
-    // This should not be needed.  The tracking bug is here:
-    // https://github.com/googleapis/nodejs-monitoring/issues/191
-    await retry(
-      async () => {
-        const result = execSync('node quickstart');
-        assert.match(result, /Done writing time series data/);
-      },
-      {
-        retries: 10,
-        onFailedAttempt: () => console.warn('Write failed, retrying...'),
-      }
-    );
+  it('should run the quickstart', async function() {
+    this.retries(8);
+    await delay(this.test); // delay the start of the test, if this is a retry.
+    const result = execSync('node quickstart');
+    assert.match(result, /Done writing time series data/);
   });
 });