meta: disallow use of `.only` in tests (#4494)

It is useful for local testing, but should never be committed. This lint
rule should help catch that during code reviews.

.eslintrc.js

@@ -32,6 +32,7 @@ module.exports = {
     // extra:
     'compat',
     'jsdoc',
+    'no-only-tests',
     'unicorn',
   ],
   parser: '@babel/eslint-parser',
@@ -496,7 +497,12 @@ module.exports = {
     },
     {
       files: ['e2e/**/*.ts', 'e2e/**/*.js', 'e2e/**/*.jsx', 'e2e/**/*.mjs'],
-      rules: { 'import/no-extraneous-dependencies': 'off', 'no-unused-expressions': 'off', 'no-console': 'off' },
+      rules: {
+        'import/no-extraneous-dependencies': 'off',
+        'no-console': 'off',
+        'no-only-tests/no-only-tests': 'error',
+        'no-unused-expressions': 'off',
+      },
     },
   ],
 }

package.json

@@ -71,6 +71,7 @@
     "eslint-plugin-jsdoc": "^40.0.0",
     "eslint-plugin-jsx-a11y": "^6.4.1",
     "eslint-plugin-markdown": "^3.0.0",
+    "eslint-plugin-no-only-tests": "^3.1.0",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prefer-import": "^0.0.1",
     "eslint-plugin-promise": "^6.0.0",

yarn.lock

@@ -8721,6 +8721,7 @@ __metadata:
     eslint-plugin-jsdoc: ^40.0.0
     eslint-plugin-jsx-a11y: ^6.4.1
     eslint-plugin-markdown: ^3.0.0
+    eslint-plugin-no-only-tests: ^3.1.0
     eslint-plugin-node: ^11.1.0
     eslint-plugin-prefer-import: ^0.0.1
     eslint-plugin-promise: ^6.0.0
@@ -16853,6 +16854,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"eslint-plugin-no-only-tests@npm:^3.1.0":
+  version: 3.1.0
+  resolution: "eslint-plugin-no-only-tests@npm:3.1.0"
+  checksum: 2a5de82f3a732dbd46792661dd0f8546cf819f76d8828968166dee35741e8039904ba473dafe1eed585f401a496d260c2c38354bb887c94bd4ced0ddca00fb62
+  languageName: node
+  linkType: hard
+
 "eslint-plugin-node@npm:^11.1.0":
   version: 11.1.0
   resolution: "eslint-plugin-node@npm:11.1.0"