test(docs-infra): ensure all redirect rules are tested (#42452)

This commit adds a test assertion to verify that all redirect rules
defined in `firebase.json` are tested, i.e. that each rule is applied to
at least one testcase from `URLS_TO_REDIRECT.txt`.

This will ensure that any redirect rules added in the future will be
tested.

PR Close #42452

aio/tests/deployment/shared/helpers.ts

@@ -12,6 +12,7 @@ import { FirebaseRedirector, FirebaseRedirectConfig } from '../../../tools/fireb
 
 
 const AIO_DIR = resolvePath(__dirname, '../../..');
+export const PATH_TO_LEGACY_URLS = resolvePath(__dirname, 'URLS_TO_REDIRECT.txt');
 
 export function getRedirector() {
   return new FirebaseRedirector(loadRedirects());
@@ -40,8 +41,7 @@ export function loadRedirects(): FirebaseRedirectConfig[] {
 }
 
 export function loadLegacyUrls() {
-  const pathToLegacyUrls = `${__dirname}/URLS_TO_REDIRECT.txt`;
-  const urls = readFileSync(pathToLegacyUrls, 'utf8')
+  const urls = readFileSync(PATH_TO_LEGACY_URLS, 'utf8')
       .split('\n')
       .filter(line => line.trim() !== '')
       .map(line => line.split(/\s*-->\s*/));

aio/tests/deployment/unit/testFirebaseRedirection.spec.ts

@@ -1,4 +1,6 @@
-import { getRedirector, loadLegacyUrls, loadLocalSitemapUrls, loadRedirects } from '../shared/helpers';
+import {
+  getRedirector, loadLegacyUrls, loadLocalSitemapUrls, loadRedirects, PATH_TO_LEGACY_URLS,
+} from '../shared/helpers';
 
 describe('firebase.json redirect config', () => {
   describe('with sitemap urls', () => {
@@ -14,6 +16,14 @@ describe('firebase.json redirect config', () => {
   describe('with legacy urls', () => {
     const redirector = getRedirector();
 
+    afterAll(() => {
+      expect(redirector.unusedRedirectConfigs)
+          .withContext(
+              'Some redirect rules from \'firebase.json\' were not tested. ' +
+              `Ensure there is at least one testcase for each redirect rule in '${PATH_TO_LEGACY_URLS}'.`)
+          .toEqual([]);
+    });
+
     loadLegacyUrls().forEach(urlPair => {
       it(`should redirect legacy URL '${urlPair[0]}'`, () => {
         const redirected = redirector.redirect(urlPair[0]);

aio/tools/firebase-test-utils/FirebaseRedirect.ts

@@ -6,7 +6,8 @@ export class FirebaseRedirect {
   source: FirebaseRedirectSource;
   destination: string;
 
-  constructor({source, regex, destination}: FirebaseRedirectConfig) {
+  constructor(readonly rawConfig: FirebaseRedirectConfig) {
+    const {source, regex, destination} = rawConfig;
     this.source = (typeof source === 'string') ?
       FirebaseRedirectSource.fromGlobPattern(source) :
       FirebaseRedirectSource.fromRegexPattern(regex!);

aio/tools/firebase-test-utils/FirebaseRedirector.spec.ts

@@ -39,4 +39,25 @@ describe('FirebaseRedirector', () => {
     ]);
     expect(() => redirector.redirect('a')).toThrowError('infinite redirect loop');
   });
+
+  it('should keep track of unused redirects', () => {
+    const redirects = [
+      { source: '/a', destination: '/A' },
+      { regex: '^/b$', destination: '/B' },
+      { source: '/c', destination: '/C' },
+    ];
+    const redirector = new FirebaseRedirector(redirects);
+
+    expect(redirector.unusedRedirectConfigs).toEqual([redirects[0], redirects[1], redirects[2]]);
+
+    redirector.redirect('/a');
+    expect(redirector.unusedRedirectConfigs).toEqual([redirects[1], redirects[2]]);
+
+    redirector.redirect('/not-redirected');
+    expect(redirector.unusedRedirectConfigs).toEqual([redirects[1], redirects[2]]);
+
+    redirector.redirect('/b');
+    redirector.redirect('/c');
+    expect(redirector.unusedRedirectConfigs).toEqual([]);
+  });
 });

aio/tools/firebase-test-utils/FirebaseRedirector.ts

@@ -6,8 +6,15 @@ export type FirebaseRedirectConfig =
 
 export class FirebaseRedirector {
   private redirects: FirebaseRedirect[];
+  private unusedRedirects: Set<FirebaseRedirect>;
+
+  get unusedRedirectConfigs(): FirebaseRedirectConfig[] {
+    return [...this.unusedRedirects].map(({rawConfig}) => rawConfig);
+  }
+
   constructor(redirects: FirebaseRedirectConfig[]) {
     this.redirects = redirects.map(redirect => new FirebaseRedirect(redirect));
+    this.unusedRedirects = new Set(this.redirects);
   }
 
   redirect(url: string): string {
@@ -28,6 +35,7 @@ export class FirebaseRedirector {
     for (const redirect of this.redirects) {
       const newUrl = redirect.replace(url);
       if (newUrl !== undefined) {
+        this.unusedRedirects.delete(redirect);
         return newUrl;
       }
     }