fix: rewrite .js to .ts imports in test files

Test files import from source using .js extensions which don't
resolve on Node 24 with module:nodenext. Apply the same .js -> .ts
import rewrite to test files as was done for source files.

Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bennypowers

packages/dev-server-esbuild/test/banner-footer.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import path from 'path';
 import { createTestServer } from '@web/dev-server-core/test-helpers';
 import { expectIncludes } from '@web/dev-server-core/test-helpers';
 

packages/dev-server-esbuild/test/browser-targets.test.ts

@@ -1,6 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
-import browserCompatData from '@mdn/browser-compat-data';
+import browserCompatData from '@mdn/browser-compat-data.ts';
 const { browsers } = browserCompatData;
 import { isLatestModernBrowser, getLatestStableMajor } from '../src/browser-targets.ts';
 

packages/dev-server-esbuild/test/json.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import path from 'path';
 import { expectIncludes, createTestServer } from '@web/dev-server-core/test-helpers';
 
 import { esbuildPlugin } from '../src/index.ts';

packages/dev-server-esbuild/test/jsx.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import path from 'path';
 import { expectIncludes, createTestServer } from '@web/dev-server-core/test-helpers';
 
 import { esbuildPlugin } from '../src/index.ts';

packages/dev-server-esbuild/test/target.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import path from 'path';
 import { createTestServer, expectIncludes } from '@web/dev-server-core/test-helpers';
 
 import { esbuildPlugin } from '../src/index.ts';

packages/dev-server-esbuild/test/tsx.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
+import path from 'path';
 import { createTestServer } from '@web/dev-server-core/test-helpers';
 import { expectIncludes, expectNotIncludes } from '@web/dev-server-core/test-helpers';
 

packages/dev-server-rollup/test/node/plugins/alias.test.ts

@@ -1,5 +1,5 @@
 import { describe, it } from 'node:test';
-import rollupAlias from '@rollup/plugin-alias';
+import rollupAlias from '@rollup/plugin-alias.ts';
 
 import { createTestServer, fetchText, expectIncludes } from '../test-helpers.ts';
 import { fromRollup } from '../../../src/fromRollup.ts';

packages/dev-server-rollup/test/node/plugins/babel.test.ts

@@ -1,7 +1,7 @@
 /// <reference types="../../../types/rollup__plugin-babel" />
 import { describe, it } from 'node:test';
 import { fileURLToPath } from 'node:url';
-import rollupBabel from '@rollup/plugin-babel';
+import rollupBabel from '@rollup/plugin-babel.ts';
 
 import { createTestServer, fetchText, expectIncludes } from '../test-helpers.ts';
 import { fromRollup } from '../../../src/index.ts';

packages/dev-server-rollup/test/node/plugins/replace.test.ts

@@ -1,5 +1,5 @@
 import { describe, it } from 'node:test';
-import rollupReplace from '@rollup/plugin-replace';
+import rollupReplace from '@rollup/plugin-replace.ts';
 
 import { createTestServer, fetchText, expectIncludes } from '../test-helpers.ts';
 import { fromRollup } from '../../../src/index.ts';

packages/test-runner-commands/test/send-mouse/sendMousePlugin.test.ts

@@ -5,8 +5,8 @@ import { runTests } from '@web/test-runner-core/test-helpers';
 import { chromeLauncher } from '@web/test-runner-chrome';
 import { webdriverLauncher } from '@web/test-runner-webdriver';
 import { playwrightLauncher } from '@web/test-runner-playwright';
-import { sendMousePlugin } from '../../dist/sendMousePlugin.ts';
-import { startSeleniumServer } from '../selenium-server.ts';
+import { sendMousePlugin } from '../../dist/sendMousePlugin.js';
+import { startSeleniumServer } from '../selenium-server.js';
 
 const __dirname = import.meta.dirname;