diff --git a/.eslintrc.json b/.eslintrc.json
index 7421a4eadb0..b552961207f 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -3,7 +3,13 @@
     "node": true
   },
   "plugins": ["jsdoc"],
-  "extends": ["eslint:recommended", "plugin:jsdoc/recommended", "prettier"],
+  "extends": [
+    "eslint:recommended",
+    "plugin:jsdoc/recommended",
+    "plugin:jest/recommended",
+    "plugin:node/recommended",
+    "prettier"
+  ],
   "globals": { "Set": true, "Symbol": true },
   "rules": {
     "array-callback-return": [
@@ -35,6 +41,7 @@
     "no-use-before-define": [2, "nofunc"],
     "no-void": 2,
     "yoda": 2,
+    "strict": 2,
 
     "jsdoc/require-jsdoc": 0,
     "jsdoc/check-param-names": 2,
@@ -47,7 +54,10 @@
     "jsdoc/require-param-name": 2,
     "jsdoc/require-param-type": 2,
     "jsdoc/require-param": 2,
-    "jsdoc/valid-types": 2
+    "jsdoc/valid-types": 2,
+
+    "node/no-unsupported-features/es-builtins": 0, // TODO
+    "node/shebang": 0
   },
   "settings": {
     "jsdoc": {
diff --git a/benchmark/benchmark.js b/benchmark/benchmark.js
index 3b4f31c7687..2d614b03bfb 100755
--- a/benchmark/benchmark.js
+++ b/benchmark/benchmark.js
@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+'use strict';
 
 var Suites = require('./suite');
 var suites = new Suites();
@@ -6,8 +7,7 @@ var suites = new Suites();
 var regexIdx = process.argv.indexOf('--regex') + 1;
 if (regexIdx > 0) {
   if (regexIdx === process.argv.length) {
-    console.error('Error: the "--regex" option requires a value');
-    process.exit(1);
+    throw new Error('Error: the "--regex" option requires a value');
   }
   suites.filter(process.argv[regexIdx]);
 }
diff --git a/benchmark/suite.js b/benchmark/suite.js
index 2f3db732e16..6a1aa4004db 100644
--- a/benchmark/suite.js
+++ b/benchmark/suite.js
@@ -1,3 +1,4 @@
+'use strict';
 var fs = require('fs');
 var path = require('path');
 
diff --git a/index.js b/index.js
index 422691cc33d..f5a6c562800 100644
--- a/index.js
+++ b/index.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * @module cheerio
  * @borrows static.load as load
diff --git a/lib/api/attributes.js b/lib/api/attributes.js
index 367e11d06cb..62bfcacaff2 100644
--- a/lib/api/attributes.js
+++ b/lib/api/attributes.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * Methods for getting and modifying attributes.
  *
diff --git a/lib/api/css.js b/lib/api/css.js
index 3786b028ee9..873ef6a1b14 100644
--- a/lib/api/css.js
+++ b/lib/api/css.js
@@ -1,3 +1,4 @@
+'use strict';
 /** @module cheerio/css */
 
 var domEach = require('../utils').domEach;
diff --git a/lib/api/forms.js b/lib/api/forms.js
index 8d627ed0ca6..46dc0747ea0 100644
--- a/lib/api/forms.js
+++ b/lib/api/forms.js
@@ -1,3 +1,4 @@
+'use strict';
 /** @module cheerio/forms */
 
 // https://github.com/jquery/jquery/blob/2.1.3/src/manipulation/var/rcheckableType.js
diff --git a/lib/api/manipulation.js b/lib/api/manipulation.js
index 516a33848bc..01b75a46834 100644
--- a/lib/api/manipulation.js
+++ b/lib/api/manipulation.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * Methods for modifying the DOM structure.
  *
diff --git a/lib/api/traversing.js b/lib/api/traversing.js
index bd417beac8e..ef12a8e8856 100644
--- a/lib/api/traversing.js
+++ b/lib/api/traversing.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * Methods for traversing the DOM structure.
  *
diff --git a/lib/cheerio.js b/lib/cheerio.js
index fc72c4de741..b03942367af 100644
--- a/lib/cheerio.js
+++ b/lib/cheerio.js
@@ -1,3 +1,4 @@
+'use strict';
 /*
   Module dependencies
 */
diff --git a/lib/options.js b/lib/options.js
index 1f3b9a0af2a..8f6a7f0eaa1 100644
--- a/lib/options.js
+++ b/lib/options.js
@@ -1,3 +1,4 @@
+'use strict';
 /** Cheerio default options. */
 exports.default = {
   xml: false,
diff --git a/lib/parse.js b/lib/parse.js
index 09abc5d89da..3c884cf5474 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1,3 +1,4 @@
+'use strict';
 /*
   Module Dependencies
 */
diff --git a/lib/parsers/htmlparser2.js b/lib/parsers/htmlparser2.js
index 0564b492c8e..ec9c20d79c8 100644
--- a/lib/parsers/htmlparser2.js
+++ b/lib/parsers/htmlparser2.js
@@ -1,2 +1,3 @@
+'use strict';
 exports.parse = require('htmlparser2').parseDocument;
 exports.render = require('dom-serializer').default;
diff --git a/lib/parsers/parse5.js b/lib/parsers/parse5.js
index 6b4c9bcb64a..870103c3f5c 100644
--- a/lib/parsers/parse5.js
+++ b/lib/parsers/parse5.js
@@ -1,3 +1,4 @@
+'use strict';
 var parse5 = require('parse5');
 var htmlparser2Adapter = require('parse5-htmlparser2-tree-adapter');
 
diff --git a/lib/static.js b/lib/static.js
index cc76a5c543b..c496efeb6d1 100644
--- a/lib/static.js
+++ b/lib/static.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * @module cheerio/static
  * @ignore
@@ -117,7 +118,7 @@ exports.html = function (dom, options) {
   options = Object.assign(
     {},
     defaultOptions,
-    this._options,
+    this ? this._options : {},
     flattenOptions(options || {})
   );
 
diff --git a/lib/utils.js b/lib/utils.js
index 95a01c476fe..aab06ce576c 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -1,3 +1,4 @@
+'use strict';
 var htmlparser2 = require('htmlparser2');
 var domhandler = require('domhandler');
 
diff --git a/package-lock.json b/package-lock.json
index f11d3a73a9e..d2b00d048e4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -757,6 +757,12 @@
         "@types/istanbul-lib-report": "*"
       }
     },
+    "@types/json-schema": {
+      "version": "7.0.6",
+      "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.6.tgz",
+      "integrity": "sha512-3c+yGKvVP5Y9TYBEibGNR+kLtijnj7mYrXRg+WpFb2X9xm04g/DXYkfg4hmzJQosc9snFNUPkbYIhu+KAm6jJw==",
+      "dev": true
+    },
     "@types/minimist": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/@types/minimist/-/minimist-1.2.1.tgz",
@@ -808,6 +814,62 @@
       "integrity": "sha512-37RSHht+gzzgYeobbG+KWryeAW8J33Nhr69cjTqSYymXVZEN9NbRYWoYlRtDhHKPVT1FyNKwaTPC1NynKZpzRA==",
       "dev": true
     },
+    "@typescript-eslint/experimental-utils": {
+      "version": "4.11.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/experimental-utils/-/experimental-utils-4.11.1.tgz",
+      "integrity": "sha512-mAlWowT4A6h0TC9F+J5pdbEhjNiEMO+kqPKQ4sc3fVieKL71dEqfkKgtcFVSX3cjSBwYwhImaQ/mXQF0oaI38g==",
+      "dev": true,
+      "requires": {
+        "@types/json-schema": "^7.0.3",
+        "@typescript-eslint/scope-manager": "4.11.1",
+        "@typescript-eslint/types": "4.11.1",
+        "@typescript-eslint/typescript-estree": "4.11.1",
+        "eslint-scope": "^5.0.0",
+        "eslint-utils": "^2.0.0"
+      }
+    },
+    "@typescript-eslint/scope-manager": {
+      "version": "4.11.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/scope-manager/-/scope-manager-4.11.1.tgz",
+      "integrity": "sha512-Al2P394dx+kXCl61fhrrZ1FTI7qsRDIUiVSuN6rTwss6lUn8uVO2+nnF4AvO0ug8vMsy3ShkbxLu/uWZdTtJMQ==",
+      "dev": true,
+      "requires": {
+        "@typescript-eslint/types": "4.11.1",
+        "@typescript-eslint/visitor-keys": "4.11.1"
+      }
+    },
+    "@typescript-eslint/types": {
+      "version": "4.11.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/types/-/types-4.11.1.tgz",
+      "integrity": "sha512-5kvd38wZpqGY4yP/6W3qhYX6Hz0NwUbijVsX2rxczpY6OXaMxh0+5E5uLJKVFwaBM7PJe1wnMym85NfKYIh6CA==",
+      "dev": true
+    },
+    "@typescript-eslint/typescript-estree": {
+      "version": "4.11.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/typescript-estree/-/typescript-estree-4.11.1.tgz",
+      "integrity": "sha512-tC7MKZIMRTYxQhrVAFoJq/DlRwv1bnqA4/S2r3+HuHibqvbrPcyf858lNzU7bFmy4mLeIHFYr34ar/1KumwyRw==",
+      "dev": true,
+      "requires": {
+        "@typescript-eslint/types": "4.11.1",
+        "@typescript-eslint/visitor-keys": "4.11.1",
+        "debug": "^4.1.1",
+        "globby": "^11.0.1",
+        "is-glob": "^4.0.1",
+        "lodash": "^4.17.15",
+        "semver": "^7.3.2",
+        "tsutils": "^3.17.1"
+      }
+    },
+    "@typescript-eslint/visitor-keys": {
+      "version": "4.11.1",
+      "resolved": "https://registry.npmjs.org/@typescript-eslint/visitor-keys/-/visitor-keys-4.11.1.tgz",
+      "integrity": "sha512-IrlBhD9bm4bdYcS8xpWarazkKXlE7iYb1HzRuyBP114mIaj5DJPo11Us1HgH60dTt41TCZXMaTCAW+OILIYPOg==",
+      "dev": true,
+      "requires": {
+        "@typescript-eslint/types": "4.11.1",
+        "eslint-visitor-keys": "^2.0.0"
+      }
+    },
     "abab": {
       "version": "2.0.5",
       "resolved": "https://registry.npmjs.org/abab/-/abab-2.0.5.tgz",
@@ -2235,6 +2297,25 @@
         "supports-hyperlinks": "^2.0.0"
       }
     },
+    "eslint-plugin-es": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-es/-/eslint-plugin-es-3.0.1.tgz",
+      "integrity": "sha512-GUmAsJaN4Fc7Gbtl8uOBlayo2DqhwWvEzykMHSCZHU3XdJ+NSzzZcVhXh3VxX5icqQ+oQdIEawXX8xkR3mIFmQ==",
+      "dev": true,
+      "requires": {
+        "eslint-utils": "^2.0.0",
+        "regexpp": "^3.0.0"
+      }
+    },
+    "eslint-plugin-jest": {
+      "version": "24.1.3",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-jest/-/eslint-plugin-jest-24.1.3.tgz",
+      "integrity": "sha512-dNGGjzuEzCE3d5EPZQ/QGtmlMotqnYWD/QpCZ1UuZlrMAdhG5rldh0N0haCvhGnUkSeuORS5VNROwF9Hrgn3Lg==",
+      "dev": true,
+      "requires": {
+        "@typescript-eslint/experimental-utils": "^4.0.1"
+      }
+    },
     "eslint-plugin-jsdoc": {
       "version": "30.7.13",
       "resolved": "https://registry.npmjs.org/eslint-plugin-jsdoc/-/eslint-plugin-jsdoc-30.7.13.tgz",
@@ -2250,6 +2331,34 @@
         "spdx-expression-parse": "^3.0.1"
       }
     },
+    "eslint-plugin-node": {
+      "version": "11.1.0",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-node/-/eslint-plugin-node-11.1.0.tgz",
+      "integrity": "sha512-oUwtPJ1W0SKD0Tr+wqu92c5xuCeQqB3hSCHasn/ZgjFdA9iDGNkNf2Zi9ztY7X+hNuMib23LNGRm6+uN+KLE3g==",
+      "dev": true,
+      "requires": {
+        "eslint-plugin-es": "^3.0.0",
+        "eslint-utils": "^2.0.0",
+        "ignore": "^5.1.1",
+        "minimatch": "^3.0.4",
+        "resolve": "^1.10.1",
+        "semver": "^6.1.0"
+      },
+      "dependencies": {
+        "ignore": {
+          "version": "5.1.8",
+          "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.1.8.tgz",
+          "integrity": "sha512-BMpfD7PpiETpBl/A6S498BaIJ6Y/ABT93ETbby2fP00v4EbvPBXWEoaR1UBPKs3iR53pJY7EtZk5KACI57i1Uw==",
+          "dev": true
+        },
+        "semver": {
+          "version": "6.3.0",
+          "resolved": "https://registry.npmjs.org/semver/-/semver-6.3.0.tgz",
+          "integrity": "sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==",
+          "dev": true
+        }
+      }
+    },
     "eslint-rule-docs": {
       "version": "1.1.217",
       "resolved": "https://registry.npmjs.org/eslint-rule-docs/-/eslint-rule-docs-1.1.217.tgz",
@@ -5065,9 +5174,9 @@
       "dev": true
     },
     "prettier-plugin-jsdoc": {
-      "version": "0.2.12",
-      "resolved": "https://registry.npmjs.org/prettier-plugin-jsdoc/-/prettier-plugin-jsdoc-0.2.12.tgz",
-      "integrity": "sha512-AijMY+SwUlsjusg1Cmubv82Zit5/Y5IlrWCXKPYrR1Axh8MNeER06prd8Rfl7WjjLI04Lih/CCsje67NzPB7kA==",
+      "version": "0.2.13",
+      "resolved": "https://registry.npmjs.org/prettier-plugin-jsdoc/-/prettier-plugin-jsdoc-0.2.13.tgz",
+      "integrity": "sha512-8b4yTPPe07TmbiLQlufQaAZk3XzRuZRYIemuxUH4yuXC4I2bqrLKPR3nq58stkcuIhRqQwKBio4npI908N4Fvw==",
       "dev": true,
       "requires": {
         "comment-parser": "^0.7.6",
@@ -6397,6 +6506,15 @@
       "integrity": "sha512-Xni35NKzjgMrwevysHTCArtLDpPvye8zV/0E4EyYn43P7/7qvQwPh9BGkHewbMulVntbigmcT7rdX3BNo9wRJg==",
       "dev": true
     },
+    "tsutils": {
+      "version": "3.18.0",
+      "resolved": "https://registry.npmjs.org/tsutils/-/tsutils-3.18.0.tgz",
+      "integrity": "sha512-D9Tu8nE3E7D1Bsf/V29oMHceMf+gnVO+pDguk/A5YRo1cLpkiQ48ZnbbS57pvvHeY+OIeNQx1vf4ASPlEtRpcA==",
+      "dev": true,
+      "requires": {
+        "tslib": "^1.8.1"
+      }
+    },
     "tunnel-agent": {
       "version": "0.6.0",
       "resolved": "https://registry.npmjs.org/tunnel-agent/-/tunnel-agent-0.6.0.tgz",
diff --git a/package.json b/package.json
index 619845d2bea..f4b6352f792 100644
--- a/package.json
+++ b/package.json
@@ -43,7 +43,9 @@
     "benchmark": "^2.1.4",
     "eslint": "^7.17.0",
     "eslint-config-prettier": "^7.1.0",
+    "eslint-plugin-jest": "^24.1.3",
     "eslint-plugin-jsdoc": "^30.7.13",
+    "eslint-plugin-node": "^11.1.0",
     "husky": "^4.3.6",
     "jest": "^26.6.3",
     "jquery": "^3.5.1",
@@ -51,7 +53,7 @@
     "jsdom": "^16.4.0",
     "lint-staged": "^10.5.3",
     "prettier": "^2.2.1",
-    "prettier-plugin-jsdoc": "^0.2.12",
+    "prettier-plugin-jsdoc": "^0.2.13",
     "tsd": "^0.14.0"
   },
   "scripts": {
@@ -68,6 +70,7 @@
     "format:prettier:raw": "prettier \"**/*.{js,ts,md,json,yml}\" --ignore-path .gitignore",
     "build:docs": "jsdoc --configure jsdoc-config.json",
     "benchmark": "node benchmark/benchmark.js --regex \"^(?!.*highmem)\"",
+    "bench": "npm run benchmark",
     "pre-commit": "lint-staged"
   },
   "prettier": {
diff --git a/test/__fixtures__/fixtures.js b/test/__fixtures__/fixtures.js
index cdfa0cccb71..79f85ca3f09 100644
--- a/test/__fixtures__/fixtures.js
+++ b/test/__fixtures__/fixtures.js
@@ -1,3 +1,4 @@
+'use strict';
 exports.fruits = [
   '<ul id="fruits">',
   '<li class="apple">Apple</li>',
diff --git a/test/api/attributes.js b/test/api/attributes.js
index 3d5176e22af..ec102e5d911 100644
--- a/test/api/attributes.js
+++ b/test/api/attributes.js
@@ -1,3 +1,4 @@
+'use strict';
 var cheerio = require('../..');
 var fruits = require('../__fixtures__/fixtures').fruits;
 var vegetables = require('../__fixtures__/fixtures').vegetables;
@@ -33,13 +34,13 @@ describe('$(...)', function () {
       expect(attr).toBe('autofocus');
     });
 
-    it('(key, value) : should set attr', function () {
+    it('(key, value) : should set one attr', function () {
       var $pear = $('.pear').attr('id', 'pear');
       expect($('#pear')).toHaveLength(1);
       expect($pear).toBeInstanceOf($);
     });
 
-    it('(key, value) : should set attr', function () {
+    it('(key, value) : should set multiple attr', function () {
       var $el = cheerio('<div></div> <div></div>').attr('class', 'pear');
 
       expect($el[0].attribs['class']).toBe('pear');
@@ -539,7 +540,7 @@ describe('$(...)', function () {
   });
 
   describe('.hasClass', function () {
-    function test(attr) {
+    function withClass(attr) {
       return cheerio('<div class="' + attr + '"></div>');
     }
 
@@ -547,18 +548,18 @@ describe('$(...)', function () {
       var cls = $('.apple').hasClass('apple');
       expect(cls).toBe(true);
 
-      expect(test('foo').hasClass('foo')).toBe(true);
-      expect(test('foo bar').hasClass('foo')).toBe(true);
-      expect(test('bar foo').hasClass('foo')).toBe(true);
-      expect(test('bar foo bar').hasClass('foo')).toBe(true);
+      expect(withClass('foo').hasClass('foo')).toBe(true);
+      expect(withClass('foo bar').hasClass('foo')).toBe(true);
+      expect(withClass('bar foo').hasClass('foo')).toBe(true);
+      expect(withClass('bar foo bar').hasClass('foo')).toBe(true);
     });
 
     it('(invalid class) : should return false', function () {
       var cls = $('#fruits').hasClass('fruits');
       expect(cls).toBe(false);
-      expect(test('foo-bar').hasClass('foo')).toBe(false);
-      expect(test('foo-bar').hasClass('foo')).toBe(false);
-      expect(test('foo-bar').hasClass('foo-ba')).toBe(false);
+      expect(withClass('foo-bar').hasClass('foo')).toBe(false);
+      expect(withClass('foo-bar').hasClass('foo')).toBe(false);
+      expect(withClass('foo-bar').hasClass('foo-ba')).toBe(false);
     });
 
     it('should check multiple classes', function () {
@@ -573,9 +574,9 @@ describe('$(...)', function () {
     });
 
     it('(empty string argument) : should return false', function () {
-      expect(test('foo').hasClass('')).toBe(false);
-      expect(test('foo bar').hasClass('')).toBe(false);
-      expect(test('foo bar').removeClass('foo').hasClass('')).toBe(false);
+      expect(withClass('foo').hasClass('')).toBe(false);
+      expect(withClass('foo bar').hasClass('')).toBe(false);
+      expect(withClass('foo bar').removeClass('foo').hasClass('')).toBe(false);
     });
   });
 
diff --git a/test/api/css.js b/test/api/css.js
index bf02f3ce378..c566a33af3e 100644
--- a/test/api/css.js
+++ b/test/api/css.js
@@ -1,3 +1,4 @@
+'use strict';
 var cheerio = require('../..');
 
 describe('$(...)', function () {
diff --git a/test/api/deprecated.js b/test/api/deprecated.js
index b49fbaac71e..ddf0c02273e 100644
--- a/test/api/deprecated.js
+++ b/test/api/deprecated.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * This file includes tests for deprecated APIs. The methods are expected to be
  * removed in the next major release of Cheerio, but their stability should be
diff --git a/test/api/forms.js b/test/api/forms.js
index 9251572b33d..17d8057eeab 100644
--- a/test/api/forms.js
+++ b/test/api/forms.js
@@ -1,3 +1,4 @@
+'use strict';
 var cheerio = require('../..');
 var forms = require('../__fixtures__/fixtures').forms;
 
diff --git a/test/api/manipulation.js b/test/api/manipulation.js
index 9b70c3de0eb..bcbe3e57fa8 100644
--- a/test/api/manipulation.js
+++ b/test/api/manipulation.js
@@ -454,7 +454,7 @@ describe('$(...)', function () {
       expect($container[0].children[0]).toBe($wrap[0]);
     });
 
-    it('(html) : should wrap elements with it', function () {
+    it('(html) : should wrap single element with it', function () {
       var parent = doc('<p>').wrapAll('<div></div>').parent();
       expect(parent).toHaveLength(1);
       expect(parent.is('div')).toBe(true);
diff --git a/test/api/traversing.js b/test/api/traversing.js
index 6b475df1ee2..eea17f020a2 100644
--- a/test/api/traversing.js
+++ b/test/api/traversing.js
@@ -1,3 +1,4 @@
+'use strict';
 var cheerio = require('../..');
 var food = require('../__fixtures__/fixtures').food;
 var fruits = require('../__fixtures__/fixtures').fruits;
@@ -13,16 +14,9 @@ describe('$(...)', function () {
 
   describe('.load', function () {
     it('should throw a TypeError if given invalid input', function () {
-      try {
-        (function () {
-          cheerio.load();
-        })();
-
-        throw new Error('Function did not throw');
-      } catch (err) {
-        expect(err).toBeInstanceOf(Error);
-        expect(err.message).toBe('cheerio.load() expects a string');
-      }
+      expect(function () {
+        cheerio.load();
+      }).toThrow('cheerio.load() expects a string');
     });
   });
 
@@ -81,16 +75,9 @@ describe('$(...)', function () {
     });
 
     it('should throw an Error if given an invalid selector', function () {
-      try {
-        (function () {
-          $('#fruits').find(':bah');
-        })();
-
-        throw new Error('Function did not throw');
-      } catch (err) {
-        expect(err).toBeInstanceOf(Error);
-        expect(err.message).toContain('unmatched pseudo-class');
-      }
+      expect(function () {
+        $('#fruits').find(':bah');
+      }).toThrow('unmatched pseudo-class');
     });
 
     describe('(cheerio object) :', function () {
@@ -464,16 +451,9 @@ describe('$(...)', function () {
     });
 
     it('(selector) : should throw an Error if given an invalid selector', function () {
-      try {
-        (function () {
-          $('.orange').siblings(':bah');
-        })();
-
-        throw new Error('Function did not throw');
-      } catch (err) {
-        expect(err).toBeInstanceOf(Error);
-        expect(err.message).toContain('unmatched pseudo-class');
-      }
+      expect(function () {
+        $('.orange').siblings(':bah');
+      }).toThrow('unmatched pseudo-class');
     });
 
     it('(selector) : does not consider the contents of siblings when filtering (GH-374)', function () {
diff --git a/test/api/utils.js b/test/api/utils.js
index 1cd19d3066e..7cec4f7a961 100644
--- a/test/api/utils.js
+++ b/test/api/utils.js
@@ -1,3 +1,4 @@
+'use strict';
 var fixtures = require('../__fixtures__/fixtures');
 var cheerio = require('../..');
 
@@ -110,15 +111,16 @@ describe('cheerio', function () {
       expect($.html()).toBe('<body><b>foo</b> <b>bar</b></body>');
     });
 
-    // TODO:
-    // it('(html) : should handle xml tag option', function() {
-    //   var $ = $.load('<body><script>oh hai</script></body>', { xml : true });
-    //   console.log($('script')[0].type);
-    //   expect($('script')[0].type).to.be('tag');
-    // });
+    it('(html) : should handle xml tag option', function () {
+      var $ = cheerio.load('<body><script><foo></script></body>', {
+        xml: true,
+      });
+      expect($('script')[0].children[0].type).toBe('tag');
+    });
 
     it('(buffer) : should accept a buffer', function () {
       var html = '<html><head></head><body>foo</body></html>';
+      // eslint-disable-next-line node/no-unsupported-features/node-builtins
       var $html = cheerio.load(Buffer.from(html));
       expect($html.html()).toBe(html);
     });
diff --git a/test/cheerio.js b/test/cheerio.js
index fe73fe466f4..674ea57f8ad 100644
--- a/test/cheerio.js
+++ b/test/cheerio.js
@@ -1,3 +1,4 @@
+'use strict';
 var htmlparser2 = require('htmlparser2');
 var cheerio = require('..');
 var fixtures = require('./__fixtures__/fixtures');
diff --git a/test/parse.js b/test/parse.js
index b0634cda273..d022eb82597 100644
--- a/test/parse.js
+++ b/test/parse.js
@@ -1,3 +1,4 @@
+'use strict';
 var parse = require('../lib/parse');
 var defaultOpts = require('../lib/options').default;
 
@@ -210,7 +211,7 @@ describe('parse', function () {
       expect(root.childNodes[0].type).toBe('directive');
     });
 
-    it('should simply return root ', function () {
+    it('should simply return root', function () {
       var oldroot = parse(basic, defaultOpts, true);
       var root = parse(oldroot, defaultOpts, true);
       expect(root).toBe(oldroot);
diff --git a/test/xml.js b/test/xml.js
index 5e780ef9236..6fe0ce82f0f 100644
--- a/test/xml.js
+++ b/test/xml.js
@@ -1,3 +1,4 @@
+'use strict';
 var cheerio = require('..');
 
 function xml(str, options) {
@@ -38,7 +39,7 @@ describe('render', function () {
   });
 
   describe('(dom)', function () {
-    it('should keep camelCase for new nodes', function () {
+    it('should not keep camelCase for new nodes', function () {
       var str = '<g><someElem someAttribute="something">hello</someElem></g>';
       expect(dom(str, { xml: false })).toBe(
         '<someelem someattribute="something">hello</someelem>'