From 5c6632746070e682c4cdc23fb62385c1739f4a67 Mon Sep 17 00:00:00 2001
From: Connor Clark <cjamcl@gmail.com>
Date: Fri, 1 Mar 2019 11:36:57 -0800
Subject: [PATCH] test(smokehouse): +/- operator (#7343)

---
 .../byte-efficiency/expectations.js           | 10 +++++++---
 lighthouse-cli/test/smokehouse/smokehouse.js  | 19 ++++++++++++-------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/lighthouse-cli/test/smokehouse/byte-efficiency/expectations.js b/lighthouse-cli/test/smokehouse/byte-efficiency/expectations.js
index 2156f2e9f03e..2c4cc4bdb9b6 100644
--- a/lighthouse-cli/test/smokehouse/byte-efficiency/expectations.js
+++ b/lighthouse-cli/test/smokehouse/byte-efficiency/expectations.js
@@ -26,9 +26,13 @@ module.exports = [
         details: {
           overallSavingsBytes: '>45000',
           overallSavingsMs: '>500',
-          items: {
-            length: 1,
-          },
+          items: [
+            {
+              url: 'http://localhost:10200/byte-efficiency/script.js',
+              wastedBytes: '46481 +/- 100',
+              wastedPercent: '87 +/- 5',
+            },
+          ],
         },
       },
       'unused-css-rules': {
diff --git a/lighthouse-cli/test/smokehouse/smokehouse.js b/lighthouse-cli/test/smokehouse/smokehouse.js
index d7f5ff316604..be6534d35bf8 100755
--- a/lighthouse-cli/test/smokehouse/smokehouse.js
+++ b/lighthouse-cli/test/smokehouse/smokehouse.js
@@ -34,8 +34,12 @@ const PROTOCOL_TIMEOUT_EXIT_CODE = 67;
 const PAGE_HUNG_EXIT_CODE = 68;
 const INSECURE_DOCUMENT_REQUEST_EXIT_CODE = 69;
 const RETRIES = 3;
-const NUMERICAL_EXPECTATION_REGEXP = /^(<=?|>=?)((\d|\.)+)$/;
 const VERBOSE = Boolean(process.env.LH_SMOKE_VERBOSE);
+const NUMBER_REGEXP = /(?:\d|\.)+/.source;
+const OPS_REGEXP = /<=?|>=?|\+\/-/.source;
+// An optional number, optional whitespace, an operator, optional whitespace, a number.
+const NUMERICAL_EXPECTATION_REGEXP =
+  new RegExp(`^(${NUMBER_REGEXP})?\\s*(${OPS_REGEXP})\\s*(${NUMBER_REGEXP})$`);
 
 /**
  * Attempt to resolve a path locally. If this fails, attempts to locate the path
@@ -149,17 +153,18 @@ function runLighthouse(url, configPath, isDebug) {
 function matchesExpectation(actual, expected) {
   if (typeof actual === 'number' && NUMERICAL_EXPECTATION_REGEXP.test(expected)) {
     const parts = expected.match(NUMERICAL_EXPECTATION_REGEXP);
-    const operator = parts[1];
-    const number = parseFloat(parts[2]);
+    const [, prefixNumber, operator, postfixNumber] = parts;
     switch (operator) {
       case '>':
-        return actual > number;
+        return actual > postfixNumber;
       case '>=':
-        return actual >= number;
+        return actual >= postfixNumber;
       case '<':
-        return actual < number;
+        return actual < postfixNumber;
       case '<=':
-        return actual <= number;
+        return actual <= postfixNumber;
+      case '+/-':
+        return Math.abs(actual - prefixNumber) <= postfixNumber;
       default:
         throw new Error(`unexpected operator ${operator}`);
     }