test: add automated tests

.html-w3c-validatorrc.json

@@ -0,0 +1,3 @@
+{
+  "files": ["./example/build/index.html", "./example/build/about.html"]
+}

.prettierignore

@@ -0,0 +1 @@
+fixtures

example/package-lock.json

@@ -36,6 +36,7 @@
         "@types/html-validator": "5.0.3",
         "@types/mock-fs": "4.13.1",
         "@types/node": "20.4.9",
+        "@types/sinon": "10.0.16",
         "@typescript-eslint/eslint-plugin": "6.3.0",
         "@typescript-eslint/parser": "6.3.0",
         "editorconfig-checker": "5.1.1",
@@ -55,6 +56,7 @@
         "rimraf": "5.0.1",
         "semantic-release": "21.0.7",
         "serve": "14.2.0",
+        "sinon": "15.2.0",
         "typescript": "5.1.6"
       },
       "engines": {

package-lock.json

@@ -29,6 +29,7 @@
         "@types/html-validator": "5.0.3",
         "@types/mock-fs": "4.13.1",
         "@types/node": "20.4.9",
+        "@types/sinon": "10.0.16",
         "@typescript-eslint/eslint-plugin": "6.3.0",
         "@typescript-eslint/parser": "6.3.0",
         "editorconfig-checker": "5.1.1",
@@ -48,6 +49,7 @@
         "rimraf": "5.0.1",
         "semantic-release": "21.0.7",
         "serve": "14.2.0",
+        "sinon": "15.2.0",
         "typescript": "5.1.6"
       },
       "engines": {
@@ -1693,6 +1695,50 @@
         "url": "https://github.com/sindresorhus/is?sponsor=1"
       }
     },
+    "node_modules/@sinonjs/commons": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@sinonjs/commons/-/commons-3.0.0.tgz",
+      "integrity": "sha512-jXBtWAF4vmdNmZgD5FoKsVLv3rPgDnLgPbU84LIJ3otV44vJlDRokVng5v8NFJdCf/da9legHcKaRuZs4L7faA==",
+      "dev": true,
+      "dependencies": {
+        "type-detect": "4.0.8"
+      }
+    },
+    "node_modules/@sinonjs/fake-timers": {
+      "version": "10.3.0",
+      "resolved": "https://registry.npmjs.org/@sinonjs/fake-timers/-/fake-timers-10.3.0.tgz",
+      "integrity": "sha512-V4BG07kuYSUkTCSBHG8G8TNhM+F19jXFWnQtzj+we8DrkpSBCee9Z3Ms8yiGer/dlmhe35/Xdgyo3/0rQKg7YA==",
+      "dev": true,
+      "dependencies": {
+        "@sinonjs/commons": "^3.0.0"
+      }
+    },
+    "node_modules/@sinonjs/samsam": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/@sinonjs/samsam/-/samsam-8.0.0.tgz",
+      "integrity": "sha512-Bp8KUVlLp8ibJZrnvq2foVhP0IVX2CIprMJPK0vqGqgrDa0OHVKeZyBykqskkrdxV6yKBPmGasO8LVjAKR3Gew==",
+      "dev": true,
+      "dependencies": {
+        "@sinonjs/commons": "^2.0.0",
+        "lodash.get": "^4.4.2",
+        "type-detect": "^4.0.8"
+      }
+    },
+    "node_modules/@sinonjs/samsam/node_modules/@sinonjs/commons": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@sinonjs/commons/-/commons-2.0.0.tgz",
+      "integrity": "sha512-uLa0j859mMrg2slwQYdO/AkrOfmH+X6LTVmNTS9CqexuE2IvVORIkSpJLqePAbEnKJ77aMmCwr1NUZ57120Xcg==",
+      "dev": true,
+      "dependencies": {
+        "type-detect": "4.0.8"
+      }
+    },
+    "node_modules/@sinonjs/text-encoding": {
+      "version": "0.7.2",
+      "resolved": "https://registry.npmjs.org/@sinonjs/text-encoding/-/text-encoding-0.7.2.tgz",
+      "integrity": "sha512-sXXKG+uL9IrKqViTtao2Ws6dy0znu9sOaP1di/jKGW1M6VssO8vlpXCQcpZ+jisQ1tTFAC5Jo/EOzFbggBagFQ==",
+      "dev": true
+    },
     "node_modules/@swc/cli": {
       "version": "0.1.62",
       "resolved": "https://registry.npmjs.org/@swc/cli/-/cli-0.1.62.tgz",
@@ -2031,6 +2077,21 @@
       "integrity": "sha512-G8hZ6XJiHnuhQKR7ZmysCeJWE08o8T0AXtk5darsCaTVsYZhhgUrq53jizaR2FvsoeCwJhlmwTjkXBY5Pn/ZHw==",
       "dev": true
     },
+    "node_modules/@types/sinon": {
+      "version": "10.0.16",
+      "resolved": "https://registry.npmjs.org/@types/sinon/-/sinon-10.0.16.tgz",
+      "integrity": "sha512-j2Du5SYpXZjJVJtXBokASpPRj+e2z+VUhCPHmM6WMfe3dpHu6iVKJMU6AiBcMp/XTAYnEj6Wc1trJUWwZ0QaAQ==",
+      "dev": true,
+      "dependencies": {
+        "@types/sinonjs__fake-timers": "*"
+      }
+    },
+    "node_modules/@types/sinonjs__fake-timers": {
+      "version": "8.1.2",
+      "resolved": "https://registry.npmjs.org/@types/sinonjs__fake-timers/-/sinonjs__fake-timers-8.1.2.tgz",
+      "integrity": "sha512-9GcLXF0/v3t80caGs5p2rRfkB+a8VBGLJZVih6CNFkx8IZ994wiKKLSRs9nuFwk1HevWs/1mnUmkApGrSGsShA==",
+      "dev": true
+    },
     "node_modules/@typescript-eslint/eslint-plugin": {
       "version": "6.3.0",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-6.3.0.tgz",
@@ -4080,6 +4141,15 @@
       "integrity": "sha512-xmHIy4F3scKVwMsQ4WnVaS8bHOx0DmVwRywosKhaILI0ywMDWPtBSku2HNxRvF7jtwDRsoEwYQSfbxj8b7RlJQ==",
       "dev": true
     },
+    "node_modules/diff": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/diff/-/diff-5.1.0.tgz",
+      "integrity": "sha512-D+mk+qE8VC/PAUrlAU34N+VfXev0ghe5ywmpqrawphmVZc1bEfn56uo9qpyGp1p4xpzOHkSW4ztBd6L7Xx4ACw==",
+      "dev": true,
+      "engines": {
+        "node": ">=0.3.1"
+      }
+    },
     "node_modules/dir-glob": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/dir-glob/-/dir-glob-3.0.1.tgz",
@@ -6523,6 +6593,12 @@
         "node": "*"
       }
     },
+    "node_modules/just-extend": {
+      "version": "4.2.1",
+      "resolved": "https://registry.npmjs.org/just-extend/-/just-extend-4.2.1.tgz",
+      "integrity": "sha512-g3UB796vUFIY90VIv/WX3L2c8CS2MdWUww3CNrYmqza1Fg0DURc2K/O4YrnklBdQarSJ/y8JnJYDGc+1iumQjg==",
+      "dev": true
+    },
     "node_modules/keyv": {
       "version": "4.5.3",
       "resolved": "https://registry.npmjs.org/keyv/-/keyv-4.5.3.tgz",
@@ -6838,6 +6914,12 @@
       "integrity": "sha512-TM9YBvyC84ZxE3rgfefxUWiQKLilstD6k7PTGt6wfbtXF8ixIJLOL3VYyV/z+ZiPLsVxAsKAFVwWlWeb2Y8Yyw==",
       "dev": true
     },
+    "node_modules/lodash.get": {
+      "version": "4.4.2",
+      "resolved": "https://registry.npmjs.org/lodash.get/-/lodash.get-4.4.2.tgz",
+      "integrity": "sha512-z+Uw/vLuy6gQe8cfaFWD7p0wVv8fJl3mbzXh33RS+0oW2wvUqiRXiQ69gLWSLpgB5/6sU+r6BlQR0MBILadqTQ==",
+      "dev": true
+    },
     "node_modules/lodash.isfunction": {
       "version": "3.0.9",
       "resolved": "https://registry.npmjs.org/lodash.isfunction/-/lodash.isfunction-3.0.9.tgz",
@@ -7489,6 +7571,43 @@
       "integrity": "sha512-EZSPZB70jiVsivaBLYDCyntd5eH8NTSMOn3rB+HxwdmKThGELLdYv8qVIMWvZEFy9w8ZZpW9h9OB32l1rGtj7g==",
       "dev": true
     },
+    "node_modules/nise": {
+      "version": "5.1.4",
+      "resolved": "https://registry.npmjs.org/nise/-/nise-5.1.4.tgz",
+      "integrity": "sha512-8+Ib8rRJ4L0o3kfmyVCL7gzrohyDe0cMFTBa2d364yIrEGMEoetznKJx899YxjybU6bL9SQkYPSBBs1gyYs8Xg==",
+      "dev": true,
+      "dependencies": {
+        "@sinonjs/commons": "^2.0.0",
+        "@sinonjs/fake-timers": "^10.0.2",
+        "@sinonjs/text-encoding": "^0.7.1",
+        "just-extend": "^4.0.2",
+        "path-to-regexp": "^1.7.0"
+      }
+    },
+    "node_modules/nise/node_modules/@sinonjs/commons": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@sinonjs/commons/-/commons-2.0.0.tgz",
+      "integrity": "sha512-uLa0j859mMrg2slwQYdO/AkrOfmH+X6LTVmNTS9CqexuE2IvVORIkSpJLqePAbEnKJ77aMmCwr1NUZ57120Xcg==",
+      "dev": true,
+      "dependencies": {
+        "type-detect": "4.0.8"
+      }
+    },
+    "node_modules/nise/node_modules/isarray": {
+      "version": "0.0.1",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-0.0.1.tgz",
+      "integrity": "sha512-D2S+3GLxWH+uhrNEcoh/fnmYeP8E8/zHl644d/jdA0g2uyXvy3sb0qxotE+ne0LtccHknQzWwZEzhak7oJ0COQ==",
+      "dev": true
+    },
+    "node_modules/nise/node_modules/path-to-regexp": {
+      "version": "1.8.0",
+      "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-1.8.0.tgz",
+      "integrity": "sha512-n43JRhlUKUAlibEJhPeir1ncUID16QnEjNpwzNdO3Lm4ywrBpBZ5oLD0I6br9evr1Y9JTqwRtAh7JLoOzAQdVA==",
+      "dev": true,
+      "dependencies": {
+        "isarray": "0.0.1"
+      }
+    },
     "node_modules/node-emoji": {
       "version": "1.11.0",
       "resolved": "https://registry.npmjs.org/node-emoji/-/node-emoji-1.11.0.tgz",
@@ -12781,6 +12900,24 @@
         "node": ">=4"
       }
     },
+    "node_modules/sinon": {
+      "version": "15.2.0",
+      "resolved": "https://registry.npmjs.org/sinon/-/sinon-15.2.0.tgz",
+      "integrity": "sha512-nPS85arNqwBXaIsFCkolHjGIkFo+Oxu9vbgmBJizLAhqe6P2o3Qmj3KCUoRkfhHtvgDhZdWD3risLHAUJ8npjw==",
+      "dev": true,
+      "dependencies": {
+        "@sinonjs/commons": "^3.0.0",
+        "@sinonjs/fake-timers": "^10.3.0",
+        "@sinonjs/samsam": "^8.0.0",
+        "diff": "^5.1.0",
+        "nise": "^5.1.4",
+        "supports-color": "^7.2.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/sinon"
+      }
+    },
     "node_modules/sisteransi": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/sisteransi/-/sisteransi-1.0.5.tgz",
@@ -13539,6 +13676,15 @@
         "node": ">= 0.8.0"
       }
     },
+    "node_modules/type-detect": {
+      "version": "4.0.8",
+      "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.8.tgz",
+      "integrity": "sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==",
+      "dev": true,
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/type-fest": {
       "version": "0.20.2",
       "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.20.2.tgz",

package.json

@@ -66,6 +66,7 @@
     "@types/html-validator": "5.0.3",
     "@types/mock-fs": "4.13.1",
     "@types/node": "20.4.9",
+    "@types/sinon": "10.0.16",
     "@typescript-eslint/eslint-plugin": "6.3.0",
     "@typescript-eslint/parser": "6.3.0",
     "editorconfig-checker": "5.1.1",
@@ -85,6 +86,7 @@
     "rimraf": "5.0.1",
     "semantic-release": "21.0.7",
     "serve": "14.2.0",
+    "sinon": "15.2.0",
     "typescript": "5.1.6"
   }
 }

src/HTMLValidatorCommand.ts

@@ -17,9 +17,9 @@ import { isExistingPath } from './utils/isExistingPath.js'
 
 export const CONFIG_FILE_NAME = '.html-w3c-validatorrc.json'
 
-const severities = ['error', 'warning', 'info'] as const
+export const SEVERITIES = ['error', 'warning', 'info'] as const
 
-export type Severity = (typeof severities)[number]
+export type Severity = (typeof SEVERITIES)[number]
 
 interface Config {
   urls?: string[]
@@ -113,22 +113,19 @@ export class HTMLValidatorCommand extends Command {
           `Invalid config file at "${configPath}". Please add URLs or files.`
         )
       }
-      const configSeverities: Severity[] = config.severities ?? [
+      const severities: Severity[] = config.severities ?? ['warning', 'error']
-        'warning',
+      for (const severity of severities) {
-        'error'
+        if (!SEVERITIES.includes(severity)) {
-      ]
-      for (const severity of configSeverities) {
-        if (!severities.includes(severity)) {
           throw new Error(
-            `Invalid config file at "${configPath}". Please add valid severities (${severities.join(
+            `Invalid config file at "${configPath}". Please add valid severities (${SEVERITIES.join(
               ', '
             )}).`
           )
         }
       }
-      if (configSeverities.length === 0) {
+      if (severities.length === 0) {
         throw new Error(
-          `Invalid config file at "${configPath}". Please add valid severities (${severities.join(
+          `Invalid config file at "${configPath}". Please add valid severities (${SEVERITIES.join(
             ', '
           )}).`
         )
@@ -169,8 +166,8 @@ export class HTMLValidatorCommand extends Command {
             }
             const hasErrors = result.messages.some((message) => {
               return (
-                configSeverities.includes(message.type as Severity) ||
+                severities.includes(message.type as Severity) ||
-                configSeverities.includes(message.subType as Severity)
+                severities.includes(message.subType as Severity)
               )
             })
             if (!hasErrors) {

src/__test__/HTMLValidatorCommand.test.ts

@@ -1,23 +1,377 @@
 import test from 'node:test'
 import assert from 'node:assert/strict'
+import path from 'node:path'
+import { PassThrough } from 'node:stream'
 
+import sinon from 'sinon'
 import { execa } from 'execa'
+import { table } from 'table'
+import chalk from 'chalk'
+import logSymbols from 'log-symbols'
 
 import { cli } from '../cli.js'
-import { HTMLValidatorCommand } from '../HTMLValidatorCommand.js'
+import {
+  HTMLValidatorCommand,
+  CONFIG_FILE_NAME,
+  SEVERITIES
+} from '../HTMLValidatorCommand.js'
+
+const FIXTURES_PATH = path.join(process.cwd(), 'src', '__test__', 'fixtures')
 
 await test('html-w3c-validator', async (t) => {
+  t.afterEach(() => {
+    sinon.restore()
+  })
+
   await t.test('should be instance of the command', async () => {
     const command = cli.process([])
     assert(command instanceof HTMLValidatorCommand)
   })
 
-  await t.test('succeeds and validate the html correctly', async () => {
+  await t.test(
+    'succeeds and validate the html correctly (example)',
+    async () => {
       const exampleURL = new URL('../../example', import.meta.url)
       process.chdir(exampleURL.pathname)
       await execa('rimraf', ['node_modules'])
       await execa('npm', ['install'])
-    const { exitCode } = await execa('npm', ['run', 'test:html-w3c-validator'])
+      const { exitCode } = await execa('npm', [
+        'run',
+        'test:html-w3c-validator'
+      ])
       assert.strictEqual(exitCode, 0)
+    }
+  )
+
+  await t.test(
+    'succeeds and validate the html correctly (example without working directory)',
+    async () => {
+      const logs: string[] = []
+      sinon.stub(console, 'log').value((log: string) => {
+        logs.push(log)
+      })
+      const consoleLogSpy = sinon.spy(console, 'log')
+      const stream = new PassThrough()
+      const exitCode = await cli.run([], {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      })
+      stream.end()
+      assert.strictEqual(exitCode, 0)
+      assert.strictEqual(
+        consoleLogSpy.calledWith(
+          logSymbols.success,
+          './example/build/index.html'
+        ),
+        true,
+        logs.join('\n')
+      )
+      assert.strictEqual(
+        consoleLogSpy.calledWith(
+          logSymbols.success,
+          './example/build/about.html'
+        ),
+        true,
+        logs.join('\n')
+      )
+    }
+  )
+
+  await t.test(
+    'succeeds and validate the html correctly (fixture)',
+    async () => {
+      const workingDirectory = path.join(FIXTURES_PATH, 'success')
+      const logs: string[] = []
+      sinon.stub(console, 'log').value((log: string) => {
+        logs.push(log)
+      })
+      const consoleLogSpy = sinon.spy(console, 'log')
+      const stream = new PassThrough()
+      const exitCode = await cli.run(
+        [`--current-working-directory=${workingDirectory}`],
+        {
+          stdin: process.stdin,
+          stdout: stream,
+          stderr: stream
+        }
+      )
+      stream.end()
+      assert.strictEqual(exitCode, 0)
+      assert.strictEqual(
+        consoleLogSpy.calledWith(logSymbols.success, './build/index.html'),
+        true,
+        logs.join('\n')
+      )
+      assert.strictEqual(
+        consoleLogSpy.calledWith(logSymbols.success, './build/about.html'),
+        true,
+        logs.join('\n')
+      )
+    }
+  )
+
+  await t.test('fails with not found config', async () => {
+    const workingDirectory = path.join(FIXTURES_PATH, 'error-config-not-found')
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` No config file found at ${configPath}. Please create "${CONFIG_FILE_NAME}".`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid JSON config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-json'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please check the JSON syntax.`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid URLs config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-urls'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please include an array of URLs.`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid files config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-files'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please include an array of files.`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid files and urls config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-files-and-urls'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please add URLs or files.`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid severities config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-severities'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please add valid severities (${SEVERITIES.join(
+            ', '
+          )}).`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid empty severities config', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-config-invalid-severities-empty'
+    )
+    const configPath = path.join(workingDirectory, CONFIG_FILE_NAME)
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') +
+          ` Invalid config file at "${configPath}". Please add valid severities (${SEVERITIES.join(
+            ', '
+          )}).`
+      ),
+      true,
+      errors.join('\n')
+    )
+  })
+
+  await t.test('fails with invalid files paths to check', async () => {
+    const workingDirectory = path.join(
+      FIXTURES_PATH,
+      'error-invalid-files-paths-to-check'
+    )
+    const htmlPath = path.resolve(workingDirectory, 'index.html')
+    const errors: string[] = []
+    sinon.stub(console, 'error').value((error: string) => {
+      errors.push(error)
+    })
+    const consoleErrorSpy = sinon.spy(console, 'error')
+    const stream = new PassThrough()
+    const exitCode = await cli.run(
+      [`--current-working-directory=${workingDirectory}`],
+      {
+        stdin: process.stdin,
+        stdout: stream,
+        stderr: stream
+      }
+    )
+    stream.end()
+    assert.strictEqual(exitCode, 1)
+    const messagesTable = [
+      [`No file found at "${htmlPath}". Please check the path.`]
+    ]
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(
+        chalk.bold.red('Error:') + ' HTML validation (W3C) failed!'
+      ),
+      true,
+      errors.join('\n')
+    )
+    assert.strictEqual(
+      consoleErrorSpy.calledWith(table(messagesTable)),
+      true,
+      errors.join('\n')
+    )
   })
 })

src/__test__/fixtures/error-config-invalid-files-and-urls/.html-w3c-validatorrc.json

@@ -0,0 +1,4 @@
+{
+  "urls": [],
+  "files": []
+}

src/__test__/fixtures/error-config-invalid-files/.html-w3c-validatorrc.json

@@ -0,0 +1,3 @@
+{
+  "files": "Invalid"
+}

src/__test__/fixtures/error-config-invalid-json/.html-w3c-validatorrc.json

@@ -0,0 +1 @@
+Invalid JSON

src/__test__/fixtures/error-config-invalid-severities-empty/.html-w3c-validatorrc.json

@@ -0,0 +1,4 @@
+{
+  "files": ["./index.html"],
+  "severities": []
+}

src/__test__/fixtures/error-config-invalid-severities-empty/index.html

@@ -0,0 +1,9 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Home</title>
+  </head>
+  <body></body>
+</html>

src/__test__/fixtures/error-config-invalid-severities/.html-w3c-validatorrc.json

@@ -0,0 +1,4 @@
+{
+  "files": ["./index.html"],
+  "severities": ["errors-invalid"]
+}

src/__test__/fixtures/error-config-invalid-severities/index.html

@@ -0,0 +1,9 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Home</title>
+  </head>
+  <body></body>
+</html>

src/__test__/fixtures/error-config-invalid-urls/.html-w3c-validatorrc.json

@@ -0,0 +1,3 @@
+{
+  "urls": "Invalid"
+}

src/__test__/fixtures/error-invalid-files-paths-to-check/.html-w3c-validatorrc.json

@@ -0,0 +1,3 @@
+{
+  "files": ["./index.html"]
+}

src/__test__/fixtures/success/.html-w3c-validatorrc.json

@@ -0,0 +1,3 @@
+{
+  "files": ["./build/index.html", "./build/about.html"]
+}

src/__test__/fixtures/success/build/about.html

@@ -0,0 +1,9 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>About</title>
+  </head>
+  <body></body>
+</html>

src/__test__/fixtures/success/build/index.html

@@ -0,0 +1,9 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Home</title>
+  </head>
+  <body></body>
+</html>