test(smartredirects): add tests for the meat of the code

scripts/redirects.js

@@ -12,7 +12,7 @@ export function activateRedirects(data) {
           replacements.shift();
           const result = v.replace(/(\$\d+|\*)/g, (matched) => {
             if (matched.startsWith('$')) {
-              return replacements[matched.slice(1)];
+              return replacements[matched.slice(1) - 1];
             }
             if (matched === '*') {
               return replacements.shift();
@@ -39,24 +39,31 @@ export async function fetchRedirects(path = '/smart-redirects.json') {
   return [];
 }
 
-export async function applyRedirects(
-  redirects = fetchRedirects(),
-  path = window.location.pathname,
-) {
+export async function getRedirect(redirects, path, currentURL) {
   const redirect = (await redirects)
     .filter((r) => typeof r.start === 'undefined' || r.start.getTime() <= Date.now())
     .find((r) => r.from.test(path));
   if (redirect) {
     const target = redirect.to(path, ...redirect.from.exec(path).slice(1));
-    const currentUrl = new URL(window.location.href);
-    const targetURL = new URL(target, currentUrl.origin);
-    // Copy all URL parameters from currentUrl to targetURL
-    currentUrl.searchParams.forEach((value, key) => {
+    const targetURL = new URL(target, currentURL.origin);
+    // Copy all URL parameters from currentURL to targetURL
+    currentURL.searchParams.forEach((value, key) => {
       targetURL.searchParams.set(key, value);
     });
 
     targetURL.searchParams.set('redirect_from', path);
-    window.location.replace(targetURL.toString());
+    return targetURL.toString();
+  }
+  return null;
+}
+
+export async function applyRedirects(
+  redirects = fetchRedirects(),
+  path = window.location.pathname,
+) {
+  const redirect = await getRedirect(redirects, path, window.location.href);
+  if (redirect) {
+    window.location.replace(redirect);
   }
   return path;
 }

tests/scripts/redirects.test.js

@@ -0,0 +1,71 @@
+import { expect } from '@esm-bundle/chai';
+import { readFile } from '@web/test-runner-commands';
+import { activateRedirects, getRedirect } from '../../scripts/redirects.js';
+/* eslint-env mocha */
+
+document.body.innerHTML = await readFile({ path: './dummy.html' });
+document.head.innerHTML = await readFile({ path: './head.html' });
+
+describe.only('Redirects', () => {
+  it('loads redirects', async () => {
+    const emptyRedirects = [];
+    const redirects = await activateRedirects(emptyRedirects);
+    expect(redirects).to.deep.equal(emptyRedirects);
+  });
+
+  it('applies applies a simple redirect', async () => {
+    const exampleRedirects = [
+      {
+        from: '/foo',
+        to: '/bar',
+        start: 1,
+      },
+    ];
+    const redirects = await activateRedirects(exampleRedirects);
+    const currentURL = new URL('https://example.com/foo');
+    const redirect = await getRedirect(redirects, '/foo', currentURL);
+    expect(redirect).to.equal('https://example.com/bar?redirect_from=%2Ffoo');
+  });
+
+  it('applies applies a redirect with a parameter', async () => {
+    const exampleRedirects = [
+      {
+        from: '/foo/*',
+        to: '/bar/*',
+        start: 1,
+      },
+    ];
+    const redirects = await activateRedirects(exampleRedirects);
+    const currentURL = new URL('https://example.com/foo/baz');
+    const redirect = await getRedirect(redirects, '/foo/baz', currentURL);
+    expect(redirect).to.equal('https://example.com/bar/baz?redirect_from=%2Ffoo%2Fbaz');
+  });
+
+  it('applies applies a redirect with multiple parameters', async () => {
+    const exampleRedirects = [
+      {
+        from: '/foo/*/*',
+        to: '/bar/*/baz/*',
+        start: 1,
+      },
+    ];
+    const redirects = await activateRedirects(exampleRedirects);
+    const currentURL = new URL('https://example.com/foo/fifi/qux');
+    const redirect = await getRedirect(redirects, '/foo/fifi/qux', currentURL);
+    expect(redirect).to.equal('https://example.com/bar/fifi/baz/qux?redirect_from=%2Ffoo%2Ffifi%2Fqux');
+  });
+
+  it('applies applies a redirect with multiple parameters and changed order', async () => {
+    const exampleRedirects = [
+      {
+        from: '/foo/*/*',
+        to: '/bar/$2/baz/$1',
+        start: 1,
+      },
+    ];
+    const redirects = await activateRedirects(exampleRedirects);
+    const currentURL = new URL('https://example.com/foo/fifi/qux');
+    const redirect = await getRedirect(redirects, '/foo/fifi/qux', currentURL);
+    expect(redirect).to.equal('https://example.com/bar/qux/baz/fifi?redirect_from=%2Ffoo%2Ffifi%2Fqux');
+  });
+});