next.js/test/unit/eslint-plugin-next/no-html-link-for-pages.test.ts

/* eslint-env jest */
import { Linter as ESLintLinterV8 } from 'eslint-v8'
import { Linter as ESLintLinterV9 } from 'eslint'
import { rules } from '@next/eslint-plugin-next'
import assert from 'assert'
import path from 'path'

const NextESLintRule = rules['no-html-link-for-pages']

const withCustomPagesDir = path.join(__dirname, 'with-custom-pages-dir')
const withNestedPagesDir = path.join(__dirname, 'with-nested-pages-dir')
const withoutPagesDir = path.join(__dirname, 'without-pages-dir')
const withAppDir = path.join(__dirname, 'with-app-dir')

const linters = {
  v8: {
    withoutPages: new ESLintLinterV8({
      cwd: withoutPagesDir,
    }),
    withApp: new ESLintLinterV8({
      cwd: withAppDir,
    }),
    withNestedPages: new ESLintLinterV8({
      cwd: withNestedPagesDir,
    }),
    withCustomPages: new ESLintLinterV8({
      cwd: withCustomPagesDir,
    }),
  },
  v9: {
    withoutPages: new ESLintLinterV9({
      cwd: withoutPagesDir,
      configType: 'eslintrc',
    }),
    withApp: new ESLintLinterV9({
      cwd: withAppDir,
      configType: 'eslintrc',
    }),
    withNestedPages: new ESLintLinterV9({
      cwd: withNestedPagesDir,
      configType: 'eslintrc',
    }),
    withCustomPages: new ESLintLinterV9({
      cwd: withCustomPagesDir,
      configType: 'eslintrc',
    }),
  },
}

const linterConfig: any = {
  rules: {
    'no-html-link-for-pages': [2],
  },
  parserOptions: {
    ecmaVersion: 2018,
    sourceType: 'module',
    ecmaFeatures: {
      modules: true,
      jsx: true,
    },
  },
}
const linterConfigWithCustomDirectory: any = {
  ...linterConfig,
  rules: {
    'no-html-link-for-pages': [
      2,
      path.join(withCustomPagesDir, 'custom-pages'),
    ],
  },
}
const linterConfigWithMultipleDirectories = {
  ...linterConfig,
  rules: {
    'no-html-link-for-pages': [
      2,
      [
        path.join(withCustomPagesDir, 'custom-pages'),
        path.join(withCustomPagesDir, 'custom-pages/list'),
      ],
    ],
  },
}
const linterConfigWithNestedContentRootDirDirectory = {
  ...linterConfig,
  settings: {
    next: {
      rootDir: path.join(withNestedPagesDir, 'demos/with-nextjs'),
    },
  },
}

for (const version of ['v8', 'v9'] as const) {
  for (const linter of Object.values(linters[version])) {
    linter.defineRules({
      'no-html-link-for-pages': NextESLintRule,
    })
  }
}

const validCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <Link href='/'>
          <a>Homepage</a>
        </Link>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const validAnchorCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='#heading'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const validExternalLinkCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='https://google.com/'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const validDownloadLinkCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/static-file.csv' download>Download</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`
const validTargetBlankLinkCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a target="_blank" href='/new-tab'>New Tab</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const validPublicFile = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/presentation.pdf'>View PDF</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const invalidStaticCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const invalidDynamicCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/list/foo/bar'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`
const secondInvalidDynamicCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/list/foo/'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const thirdInvalidDynamicCode = `
import Link from 'next/link';

export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/list/lorem-ipsum/'>Homepage</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`
const validInterceptedRouteCode = `
import Link from 'next/link';
export class Blah extends Head {
  render() {
    return (
      <div>
        <Link href='/photo/1/'>Photo</Link>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`

const invalidInterceptedRouteCode = `
import Link from 'next/link';
export class Blah extends Head {
  render() {
    return (
      <div>
        <a href='/photo/1/'>Photo</a>
        <h1>Hello title</h1>
      </div>
    );
  }
}
`
describe('no-html-link-for-pages', function () {
  for (const version of ['v8', 'v9']) {
    it(`does not print warning when there are "pages" or "app" directories with rootDir in context settings (${version})`, function () {
      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation()
      linters[version].withNestedPages.verify(
        validCode,
        linterConfigWithNestedContentRootDirDirectory,
        { filename: 'foo.js' }
      )
      expect(consoleSpy).not.toHaveBeenCalled()
      consoleSpy.mockRestore()
    })
    it(`prints warning when there are no "pages" or "app" directories (${version})`, function () {
      // TODO(jiwon): unskip v8 test
      // If this test runs standalone, it correctly calls warning,
      // but on the second run, it doesn't. Skip the v8 test for now as
      // there were no rule changes. Maybe related to:
      // https://github.com/facebook/react/issues/7047#issuecomment-228614964
      if (version === 'v8') return

      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation()
      linters[version].withoutPages.verify(validCode, linterConfig, {
        filename: 'foo.js',
      })
      expect(consoleSpy).toHaveBeenCalledWith(
        `Pages directory cannot be found at ${path.join(
          withoutPagesDir,
          'pages'
        )} or ${path.join(
          withoutPagesDir,
          'src',
          'pages'
        )}. If using a custom path, please configure with the \`no-html-link-for-pages\` rule in your eslint config file.`
      )
      consoleSpy.mockRestore()
    })
    it(`does not print warning when there is "app" directory and no "pages" directory (${version})`, function () {
      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation()
      linters[version].withApp.verify(validCode, linterConfig, {
        filename: 'foo.js',
      })
      expect(consoleSpy).not.toHaveBeenCalled()
      consoleSpy.mockRestore()
    })
    it(`valid link element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid link element with multiple directories (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validCode,
        linterConfigWithMultipleDirectories,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid anchor element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validAnchorCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid external link element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validExternalLinkCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid download link element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validDownloadLinkCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid target="_blank" link element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validTargetBlankLinkCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid public file link element (${version})`, function () {
      const report = linters[version].withCustomPages.verify(
        validPublicFile,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`invalid static route (${version})`, function () {
      const [report] = linters[version].withCustomPages.verify(
        invalidStaticCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.notEqual(report, undefined, 'No lint errors found.')
      assert.equal(
        report.message,
        'Do not use an `<a>` element to navigate to `/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
    })
    it(`invalid dynamic route (${version})`, function () {
      const [report] = linters[version].withCustomPages.verify(
        invalidDynamicCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.notEqual(report, undefined, 'No lint errors found.')
      assert.equal(
        report.message,
        'Do not use an `<a>` element to navigate to `/list/foo/bar/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
      const [secondReport] = linters[version].withCustomPages.verify(
        secondInvalidDynamicCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.notEqual(secondReport, undefined, 'No lint errors found.')
      assert.equal(
        secondReport.message,
        'Do not use an `<a>` element to navigate to `/list/foo/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
      const [thirdReport] = linters[version].withCustomPages.verify(
        thirdInvalidDynamicCode,
        linterConfigWithCustomDirectory,
        { filename: 'foo.js' }
      )
      assert.notEqual(thirdReport, undefined, 'No lint errors found.')
      assert.equal(
        thirdReport.message,
        'Do not use an `<a>` element to navigate to `/list/lorem-ipsum/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
    })
    it(`valid link element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(validCode, linterConfig, {
        filename: 'foo.js',
      })
      assert.deepEqual(report, [])
    })
    it(`valid link element with multiple directories with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(validCode, linterConfig, {
        filename: 'foo.js',
      })
      assert.deepEqual(report, [])
    })
    it(`valid anchor element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validAnchorCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid external link element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validExternalLinkCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid download link element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validDownloadLinkCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid target="_blank" link element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validTargetBlankLinkCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`valid public file link element with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validPublicFile,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`invalid static route with appDir (${version})`, function () {
      const [report] = linters[version].withApp.verify(
        invalidStaticCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.notEqual(report, undefined, 'No lint errors found.')
      assert.equal(
        report.message,
        'Do not use an `<a>` element to navigate to `/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
    })
    it(`invalid dynamic route with appDir (${version})`, function () {
      const [report] = linters[version].withApp.verify(
        invalidDynamicCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.notEqual(report, undefined, 'No lint errors found.')
      assert.equal(
        report.message,
        'Do not use an `<a>` element to navigate to `/list/foo/bar/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
      const [secondReport] = linters[version].withApp.verify(
        secondInvalidDynamicCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.notEqual(secondReport, undefined, 'No lint errors found.')
      assert.equal(
        secondReport.message,
        'Do not use an `<a>` element to navigate to `/list/foo/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
      const [thirdReport] = linters[version].withApp.verify(
        thirdInvalidDynamicCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.notEqual(thirdReport, undefined, 'No lint errors found.')
      assert.equal(
        thirdReport.message,
        'Do not use an `<a>` element to navigate to `/list/lorem-ipsum/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
    })
    it(`valid intercepted route with appDir (${version})`, function () {
      const report = linters[version].withApp.verify(
        validInterceptedRouteCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.deepEqual(report, [])
    })
    it(`invalid intercepted route with appDir (${version})`, function () {
      const [report] = linters[version].withApp.verify(
        invalidInterceptedRouteCode,
        linterConfig,
        { filename: 'foo.js' }
      )
      assert.notEqual(report, undefined, 'No lint errors found.')
      assert.equal(
        report.message,
        'Do not use an `<a>` element to navigate to `/photo/1/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages'
      )
    })
  }
})