fix(@angular/build): serve build assets and styles in vitest

packages/angular/build/src/builders/unit-test/runners/vitest/plugins.ts

@@ -10,6 +10,7 @@ import assert from 'node:assert';
 import { readFile } from 'node:fs/promises';
 import path from 'node:path';
 import type { VitestPlugin } from 'vitest/node';
+import { createBuildAssetsMiddleware } from '../../../../tools/vite/middlewares/assets-middleware';
 import { toPosixPath } from '../../../../utils/path';
 import type { ResultFile } from '../../../application/results';
 import type { NormalizedUnitTestBuilderOptions } from '../../options';
@@ -129,6 +130,11 @@ export function createVitestPlugins(
                   };
                 }
               },
+              configureServer: (server) => {
+                server.middlewares.use(
+                  createBuildAssetsMiddleware(server.config.base, buildResultFiles),
+                );
+              },
             },
             {
               name: 'angular:html-index',

packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts

@@ -12,6 +12,7 @@ import { readFileSync } from 'node:fs';
 import type { ServerResponse } from 'node:http';
 import { extname } from 'node:path';
 import type { Connect, ViteDevServer } from 'vite';
+import { ResultFile } from '../../../builders/application/results';
 import { AngularMemoryOutputFiles, AngularOutputAssets, pathnameWithoutBasePath } from '../utils';
 
 export interface ComponentStyleRecord {
@@ -214,3 +215,45 @@ function checkAndHandleEtag(
 
   return false;
 }
+
+export function createBuildAssetsMiddleware(
+  basePath: string,
+  buildResultFiles: ReadonlyMap<string, ResultFile>,
+  readHandler: (path: string) => Buffer = readFileSync,
+): Connect.NextHandleFunction {
+  return function buildAssetsMiddleware(req, res, next) {
+    if (req.url === undefined || res.writableEnded) {
+      return;
+    }
+
+    // Parse the incoming request.
+    // The base of the URL is unused but required to parse the URL.
+    const pathname = pathnameWithoutBasePath(req.url, basePath);
+    const extension = extname(pathname);
+    if (extension && !/\.[mc]?[jt]s(?:\.map)?$/.test(extension)) {
+      const outputFile = buildResultFiles.get(pathname.slice(1));
+      if (outputFile) {
+        const contents =
+          outputFile.origin === 'memory' ? outputFile.contents : readHandler(outputFile.inputPath);
+
+        const etag = `W/${createHash('sha256').update(contents).digest('hex')}`;
+        if (checkAndHandleEtag(req, res, etag)) {
+          return;
+        }
+
+        const mimeType = lookupMimeType(extension);
+        if (mimeType) {
+          res.setHeader('Content-Type', mimeType);
+        }
+
+        res.setHeader('ETag', etag);
+        res.setHeader('Cache-Control', 'no-cache');
+        res.end(contents);
+
+        return;
+      }
+    }
+
+    next();
+  };
+}