From 30744d0beb834c7f04a32bf1a2e6821c5e6bdfe5 Mon Sep 17 00:00:00 2001
From: Paul Sealock <psealock@gmail.com>
Date: Thu, 9 Sep 2021 23:28:45 +1200
Subject: [PATCH] ESLint Plugin: Use Jest related rules only when the package
 is installed (#33120)

* Add Jest to eslint plugin dependencies

* Add test rules only when jest is installed

Co-authored-by: Grzegorz Ziolkowski <grzegorz@gziolo.pl>
---
 packages/eslint-plugin/CHANGELOG.md            |  4 ++++
 .../configs/recommended-with-formatting.js     | 18 ++++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/packages/eslint-plugin/CHANGELOG.md b/packages/eslint-plugin/CHANGELOG.md
index 2ae76dde0321c9..7f4f0701deb9b3 100644
--- a/packages/eslint-plugin/CHANGELOG.md
+++ b/packages/eslint-plugin/CHANGELOG.md
@@ -6,6 +6,10 @@
 
 -   The bundled `eslint-plugin-jsdoc` dependency has been updated from requiring `^34.1.0` to requiring `^36.0.8` ([#34338](https://github.com/WordPress/gutenberg/pull/34338)).
 
+### Bug Fix
+
+-   Use Jest related rules only when the `jest` package is installed ([#33120](https://github.com/WordPress/gutenberg/pull/33120)).
+
 ## 9.1.2 (2021-09-09)
 
 ### Bug Fix
diff --git a/packages/eslint-plugin/configs/recommended-with-formatting.js b/packages/eslint-plugin/configs/recommended-with-formatting.js
index 51970f2c238cf1..a51697c9112ba2 100644
--- a/packages/eslint-plugin/configs/recommended-with-formatting.js
+++ b/packages/eslint-plugin/configs/recommended-with-formatting.js
@@ -1,4 +1,9 @@
-module.exports = {
+/**
+ * Internal dependencies
+ */
+const { isPackageInstalled } = require( '../utils' );
+
+const config = {
 	parser: 'babel-eslint',
 	extends: [
 		require.resolve( './jsx-a11y.js' ),
@@ -27,7 +32,10 @@ module.exports = {
 		'import/default': 'warn',
 		'import/named': 'warn',
 	},
-	overrides: [
+};
+
+if ( isPackageInstalled( 'jest' ) ) {
+	config.overrides = [
 		{
 			// Unit test files and their helpers only.
 			files: [ '**/@(test|__tests__)/**/*.js', '**/?(*.)test.js' ],
@@ -38,5 +46,7 @@ module.exports = {
 			files: [ '**/specs/**/*.js', '**/?(*.)spec.js' ],
 			extends: [ require.resolve( './test-e2e.js' ) ],
 		},
-	],
-};
+	];
+}
+
+module.exports = config;