diff --git a/.eslintrc.json b/.eslintrc.json
index 6988582250d2..52aefec666f7 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -15,6 +15,7 @@
     "bazel-out",
     "dist-schema",
     "goldens/public-api",
+    "modules/testing/builder/projects",
     "packages/angular_devkit/build_angular/src/babel-bazel.d.ts",
     "packages/angular_devkit/build_angular/test",
     "packages/angular_devkit/build_webpack/test",
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d269cba7c4d0..e1bf2304e131 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -103,7 +103,9 @@ jobs:
         uses: angular/dev-infra/github-actions/bazel/configure-remote@f8b2efa171f4ebec4d0cb3d5c5d4f7cb680f2af9
       - name: Install node modules
         run: yarn install --frozen-lockfile
-      - name: Run tests
+      - name: Run module tests
+        run: yarn bazel test //modules/...
+      - name: Run package tests
         run: yarn bazel test //packages/...
 
   e2e:
diff --git a/.prettierignore b/.prettierignore
index 20472fa0fa4a..c78211cd0633 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -2,6 +2,7 @@
 /docs/design/analytics.md
 /dist-schema/
 /goldens/public-api
+/modules/testing/builder/projects/
 /packages/angular_devkit/build_angular/test/
 /packages/angular_devkit/core/src/workspace/json/test/
 /packages/angular_devkit/schematics_cli/blank/project-files/
diff --git a/modules/testing/builder/BUILD.bazel b/modules/testing/builder/BUILD.bazel
new file mode 100644
index 000000000000..bcc6d347cbec
--- /dev/null
+++ b/modules/testing/builder/BUILD.bazel
@@ -0,0 +1,45 @@
+load("@npm//@bazel/jasmine:index.bzl", "jasmine_node_test")
+load("//tools:defaults.bzl", "ts_library")
+
+package(default_visibility = ["//visibility:public"])
+
+ts_library(
+    name = "builder",
+    testonly = True,
+    srcs = glob(
+        include = [
+            "src/**/*.ts",
+        ],
+        exclude = [
+            "src/**/*_spec.ts",
+        ],
+    ),
+    data = glob(["projects/**/*"]),
+    deps = [
+        "//packages/angular_devkit/architect",
+        "//packages/angular_devkit/architect/node",
+        "//packages/angular_devkit/architect/testing",
+        "//packages/angular_devkit/core",
+        "//packages/angular_devkit/core/node",
+        "@npm//rxjs",
+    ],
+)
+
+ts_library(
+    name = "unit_test_lib",
+    testonly = True,
+    srcs = glob(
+        include = [
+            "src/**/*_spec.ts",
+        ],
+    ),
+    deps = [
+        ":builder",
+        "//packages/angular_devkit/architect/testing",
+    ],
+)
+
+jasmine_node_test(
+    name = "unit_test",
+    srcs = [":unit_test_lib"],
+)
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/.browserslistrc b/modules/testing/builder/projects/hello-world-app/.browserslistrc
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/.browserslistrc
rename to modules/testing/builder/projects/hello-world-app/.browserslistrc
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/.editorconfig b/modules/testing/builder/projects/hello-world-app/.editorconfig
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/.editorconfig
rename to modules/testing/builder/projects/hello-world-app/.editorconfig
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/.gitignore b/modules/testing/builder/projects/hello-world-app/.gitignore
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/.gitignore
rename to modules/testing/builder/projects/hello-world-app/.gitignore
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/README.md b/modules/testing/builder/projects/hello-world-app/README.md
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/README.md
rename to modules/testing/builder/projects/hello-world-app/README.md
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/angular.json b/modules/testing/builder/projects/hello-world-app/angular.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/angular.json
rename to modules/testing/builder/projects/hello-world-app/angular.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/e2e/app.e2e-spec.ts b/modules/testing/builder/projects/hello-world-app/e2e/app.e2e-spec.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/e2e/app.e2e-spec.ts
rename to modules/testing/builder/projects/hello-world-app/e2e/app.e2e-spec.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/e2e/app.po.ts b/modules/testing/builder/projects/hello-world-app/e2e/app.po.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/e2e/app.po.ts
rename to modules/testing/builder/projects/hello-world-app/e2e/app.po.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/e2e/tsconfig.e2e.json b/modules/testing/builder/projects/hello-world-app/e2e/tsconfig.e2e.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/e2e/tsconfig.e2e.json
rename to modules/testing/builder/projects/hello-world-app/e2e/tsconfig.e2e.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/karma.conf.js b/modules/testing/builder/projects/hello-world-app/karma.conf.js
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/karma.conf.js
rename to modules/testing/builder/projects/hello-world-app/karma.conf.js
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/protractor.conf.js b/modules/testing/builder/projects/hello-world-app/protractor.conf.js
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/protractor.conf.js
rename to modules/testing/builder/projects/hello-world-app/protractor.conf.js
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.css b/modules/testing/builder/projects/hello-world-app/src/app/app.component.css
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.css
rename to modules/testing/builder/projects/hello-world-app/src/app/app.component.css
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.html b/modules/testing/builder/projects/hello-world-app/src/app/app.component.html
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.html
rename to modules/testing/builder/projects/hello-world-app/src/app/app.component.html
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.spec.ts b/modules/testing/builder/projects/hello-world-app/src/app/app.component.spec.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.spec.ts
rename to modules/testing/builder/projects/hello-world-app/src/app/app.component.spec.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.ts b/modules/testing/builder/projects/hello-world-app/src/app/app.component.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.component.ts
rename to modules/testing/builder/projects/hello-world-app/src/app/app.component.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.module.server.ts b/modules/testing/builder/projects/hello-world-app/src/app/app.module.server.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.module.server.ts
rename to modules/testing/builder/projects/hello-world-app/src/app/app.module.server.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.module.ts b/modules/testing/builder/projects/hello-world-app/src/app/app.module.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/app/app.module.ts
rename to modules/testing/builder/projects/hello-world-app/src/app/app.module.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/assets/.gitkeep b/modules/testing/builder/projects/hello-world-app/src/assets/.gitkeep
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/assets/.gitkeep
rename to modules/testing/builder/projects/hello-world-app/src/assets/.gitkeep
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/favicon.ico b/modules/testing/builder/projects/hello-world-app/src/favicon.ico
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/favicon.ico
rename to modules/testing/builder/projects/hello-world-app/src/favicon.ico
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/index.html b/modules/testing/builder/projects/hello-world-app/src/index.html
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/index.html
rename to modules/testing/builder/projects/hello-world-app/src/index.html
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/locale/messages.xlf b/modules/testing/builder/projects/hello-world-app/src/locale/messages.xlf
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/locale/messages.xlf
rename to modules/testing/builder/projects/hello-world-app/src/locale/messages.xlf
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/main.server.ts b/modules/testing/builder/projects/hello-world-app/src/main.server.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/main.server.ts
rename to modules/testing/builder/projects/hello-world-app/src/main.server.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/main.ts b/modules/testing/builder/projects/hello-world-app/src/main.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/main.ts
rename to modules/testing/builder/projects/hello-world-app/src/main.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/ngsw-config.json b/modules/testing/builder/projects/hello-world-app/src/ngsw-config.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/ngsw-config.json
rename to modules/testing/builder/projects/hello-world-app/src/ngsw-config.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/polyfills.ts b/modules/testing/builder/projects/hello-world-app/src/polyfills.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/polyfills.ts
rename to modules/testing/builder/projects/hello-world-app/src/polyfills.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/spectrum.png b/modules/testing/builder/projects/hello-world-app/src/spectrum.png
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/spectrum.png
rename to modules/testing/builder/projects/hello-world-app/src/spectrum.png
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/styles.css b/modules/testing/builder/projects/hello-world-app/src/styles.css
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/styles.css
rename to modules/testing/builder/projects/hello-world-app/src/styles.css
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.app.json b/modules/testing/builder/projects/hello-world-app/src/tsconfig.app.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.app.json
rename to modules/testing/builder/projects/hello-world-app/src/tsconfig.app.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.server.json b/modules/testing/builder/projects/hello-world-app/src/tsconfig.server.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.server.json
rename to modules/testing/builder/projects/hello-world-app/src/tsconfig.server.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.spec.json b/modules/testing/builder/projects/hello-world-app/src/tsconfig.spec.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.spec.json
rename to modules/testing/builder/projects/hello-world-app/src/tsconfig.spec.json
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/src/typings.d.ts b/modules/testing/builder/projects/hello-world-app/src/typings.d.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/src/typings.d.ts
rename to modules/testing/builder/projects/hello-world-app/src/typings.d.ts
diff --git a/packages/angular_devkit/build_angular/test/hello-world-app/tsconfig.json b/modules/testing/builder/projects/hello-world-app/tsconfig.json
similarity index 100%
rename from packages/angular_devkit/build_angular/test/hello-world-app/tsconfig.json
rename to modules/testing/builder/projects/hello-world-app/tsconfig.json
diff --git a/packages/angular_devkit/build_angular/src/testing/builder-harness.ts b/modules/testing/builder/src/builder-harness.ts
similarity index 99%
rename from packages/angular_devkit/build_angular/src/testing/builder-harness.ts
rename to modules/testing/builder/src/builder-harness.ts
index 05ba0d5d2df5..504b973dd9dc 100644
--- a/packages/angular_devkit/build_angular/src/testing/builder-harness.ts
+++ b/modules/testing/builder/src/builder-harness.ts
@@ -6,6 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+/* eslint-disable import/no-extraneous-dependencies */
+
 import {
   BuilderContext,
   BuilderHandlerFn,
diff --git a/packages/angular_devkit/build_angular/src/testing/builder-harness_spec.ts b/modules/testing/builder/src/builder-harness_spec.ts
similarity index 98%
rename from packages/angular_devkit/build_angular/src/testing/builder-harness_spec.ts
rename to modules/testing/builder/src/builder-harness_spec.ts
index 86d22e1808a7..98a4cc368a1f 100644
--- a/packages/angular_devkit/build_angular/src/testing/builder-harness_spec.ts
+++ b/modules/testing/builder/src/builder-harness_spec.ts
@@ -6,6 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+/* eslint-disable import/no-extraneous-dependencies */
+
 import { TestProjectHost } from '@angular-devkit/architect/testing';
 import { BuilderHarness } from './builder-harness';
 
diff --git a/packages/angular_devkit/build_angular/src/testing/file-watching.ts b/modules/testing/builder/src/file-watching.ts
similarity index 80%
rename from packages/angular_devkit/build_angular/src/testing/file-watching.ts
rename to modules/testing/builder/src/file-watching.ts
index 8263fb874ef6..7aad21c7ac97 100644
--- a/packages/angular_devkit/build_angular/src/testing/file-watching.ts
+++ b/modules/testing/builder/src/file-watching.ts
@@ -6,10 +6,17 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {
-  BuilderWatcherCallback,
-  BuilderWatcherFactory,
-} from '../tools/webpack/plugins/builder-watch-plugin';
+type BuilderWatcherCallback = (
+  events: Array<{ path: string; type: 'created' | 'modified' | 'deleted'; time?: number }>,
+) => void;
+
+interface BuilderWatcherFactory {
+  watch(
+    files: Iterable<string>,
+    directories: Iterable<string>,
+    callback: BuilderWatcherCallback,
+  ): { close(): void };
+}
 
 class WatcherDescriptor {
   constructor(
diff --git a/modules/testing/builder/src/index.ts b/modules/testing/builder/src/index.ts
new file mode 100644
index 000000000000..9de773e1c456
--- /dev/null
+++ b/modules/testing/builder/src/index.ts
@@ -0,0 +1,15 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+export {
+  BuilderHarness,
+  BuilderHarnessExecutionOptions,
+  BuilderHarnessExecutionResult,
+} from './builder-harness';
+export { HarnessFileMatchers, JasmineBuilderHarness, describeBuilder } from './jasmine-helpers';
+export * from './test-utils';
diff --git a/packages/angular_devkit/build_angular/src/testing/jasmine-helpers.ts b/modules/testing/builder/src/jasmine-helpers.ts
similarity index 100%
rename from packages/angular_devkit/build_angular/src/testing/jasmine-helpers.ts
rename to modules/testing/builder/src/jasmine-helpers.ts
diff --git a/modules/testing/builder/src/test-utils.ts b/modules/testing/builder/src/test-utils.ts
new file mode 100644
index 000000000000..a710c2b6b1e6
--- /dev/null
+++ b/modules/testing/builder/src/test-utils.ts
@@ -0,0 +1,176 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/* eslint-disable import/no-extraneous-dependencies */
+
+import { Architect, BuilderOutput, ScheduleOptions, Target } from '@angular-devkit/architect';
+import { WorkspaceNodeModulesArchitectHost } from '@angular-devkit/architect/node';
+import { TestProjectHost, TestingArchitectHost } from '@angular-devkit/architect/testing';
+import {
+  Path,
+  getSystemPath,
+  join,
+  json,
+  normalize,
+  schema,
+  virtualFs,
+  workspaces,
+} from '@angular-devkit/core';
+import { firstValueFrom } from 'rxjs';
+
+// Default timeout for large specs is 2.5 minutes.
+jasmine.DEFAULT_TIMEOUT_INTERVAL = 150000;
+
+export const workspaceRoot = join(normalize(__dirname), `../projects/hello-world-app/`);
+export const host = new TestProjectHost(workspaceRoot);
+export const outputPath: Path = normalize('dist');
+
+export const browserTargetSpec = { project: 'app', target: 'build' };
+export const devServerTargetSpec = { project: 'app', target: 'serve' };
+export const extractI18nTargetSpec = { project: 'app', target: 'extract-i18n' };
+export const karmaTargetSpec = { project: 'app', target: 'test' };
+export const tslintTargetSpec = { project: 'app', target: 'lint' };
+export const protractorTargetSpec = { project: 'app-e2e', target: 'e2e' };
+
+export async function createArchitect(workspaceRoot: Path) {
+  const registry = new schema.CoreSchemaRegistry();
+  registry.addPostTransform(schema.transforms.addUndefinedDefaults);
+  const workspaceSysPath = getSystemPath(workspaceRoot);
+
+  const { workspace } = await workspaces.readWorkspace(
+    workspaceSysPath,
+    workspaces.createWorkspaceHost(host),
+  );
+  const architectHost = new TestingArchitectHost(
+    workspaceSysPath,
+    workspaceSysPath,
+    new WorkspaceNodeModulesArchitectHost(workspace, workspaceSysPath),
+  );
+  const architect = new Architect(architectHost, registry);
+
+  return {
+    workspace,
+    architectHost,
+    architect,
+  };
+}
+
+export interface BrowserBuildOutput {
+  output: BuilderOutput;
+  files: { [file: string]: Promise<string> };
+}
+
+export async function browserBuild(
+  architect: Architect,
+  host: virtualFs.Host,
+  target: Target,
+  overrides?: json.JsonObject,
+  scheduleOptions?: ScheduleOptions,
+): Promise<BrowserBuildOutput> {
+  const run = await architect.scheduleTarget(target, overrides, scheduleOptions);
+  const output = (await run.result) as BuilderOutput & { outputs: { path: string }[] };
+  expect(output.success).toBe(true);
+
+  if (!output.success) {
+    await run.stop();
+
+    return {
+      output,
+      files: {},
+    };
+  }
+
+  const [{ path }] = output.outputs;
+  expect(path).toBeTruthy();
+  const outputPath = normalize(path);
+
+  const fileNames = await firstValueFrom(host.list(outputPath));
+  const files = fileNames.reduce((acc: { [name: string]: Promise<string> }, path) => {
+    let cache: Promise<string> | null = null;
+    Object.defineProperty(acc, path, {
+      enumerable: true,
+      get() {
+        if (cache) {
+          return cache;
+        }
+        if (!fileNames.includes(path)) {
+          return Promise.reject('No file named ' + path);
+        }
+        cache = firstValueFrom(host.read(join(outputPath, path))).then((content) =>
+          virtualFs.fileBufferToString(content),
+        );
+
+        return cache;
+      },
+    });
+
+    return acc;
+  }, {});
+
+  await run.stop();
+
+  return {
+    output,
+    files,
+  };
+}
+
+export const lazyModuleFiles: { [path: string]: string } = {
+  'src/app/lazy/lazy-routing.module.ts': `
+    import { NgModule } from '@angular/core';
+    import { Routes, RouterModule } from '@angular/router';
+
+    const routes: Routes = [];
+
+    @NgModule({
+      imports: [RouterModule.forChild(routes)],
+      exports: [RouterModule]
+    })
+    export class LazyRoutingModule { }
+  `,
+  'src/app/lazy/lazy.module.ts': `
+    import { NgModule } from '@angular/core';
+    import { CommonModule } from '@angular/common';
+
+    import { LazyRoutingModule } from './lazy-routing.module';
+
+    @NgModule({
+      imports: [
+        CommonModule,
+        LazyRoutingModule
+      ],
+      declarations: []
+    })
+    export class LazyModule { }
+  `,
+};
+
+export const lazyModuleFnImport: { [path: string]: string } = {
+  'src/app/app.module.ts': `
+    import { BrowserModule } from '@angular/platform-browser';
+    import { NgModule } from '@angular/core';
+
+    import { AppComponent } from './app.component';
+    import { RouterModule } from '@angular/router';
+
+    @NgModule({
+      declarations: [
+        AppComponent
+      ],
+      imports: [
+        BrowserModule,
+        RouterModule.forRoot([
+          { path: 'lazy', loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule) }
+        ])
+      ],
+      providers: [],
+      bootstrap: [AppComponent]
+    })
+    export class AppModule { }
+`,
+};
diff --git a/packages/angular_devkit/build_angular/BUILD.bazel b/packages/angular_devkit/build_angular/BUILD.bazel
index f220ff5bfad3..db6ea2d6481b 100644
--- a/packages/angular_devkit/build_angular/BUILD.bazel
+++ b/packages/angular_devkit/build_angular/BUILD.bazel
@@ -3,10 +3,10 @@
 # Use of this source code is governed by an MIT-style license that can be
 # found in the LICENSE file at https://angular.io/license
 
+load("@npm//@angular/build-tooling/bazel/api-golden:index.bzl", "api_golden_test_npm_package")
 load("@npm//@bazel/jasmine:index.bzl", "jasmine_node_test")
 load("//tools:defaults.bzl", "pkg_npm", "ts_library")
 load("//tools:ts_json_schema.bzl", "ts_json_schema")
-load("@npm//@angular/build-tooling/bazel/api-golden:index.bzl", "api_golden_test_npm_package")
 
 licenses(["notice"])
 
@@ -285,7 +285,6 @@ ts_library(
     testonly = True,
     srcs = glob(
         include = [
-            "src/test-utils.ts",
             "src/testing/**/*.ts",
             "src/**/tests/*.ts",
         ],
@@ -297,6 +296,7 @@ ts_library(
     tsconfig = "//:tsconfig-test.json",
     deps = [
         ":build_angular",
+        "//modules/testing/builder",
         "//packages/angular_devkit/architect",
         "//packages/angular_devkit/architect/node",
         "//packages/angular_devkit/architect/testing",
@@ -394,6 +394,7 @@ LARGE_SPECS = {
             # Dependencies needed to compile and run the specs themselves.
             ":build_angular",
             ":build_angular_test_utils",
+            "//modules/testing/builder",
             "//packages/angular_devkit/architect",
             "//packages/angular_devkit/architect/node",
             "//packages/angular_devkit/architect/testing",
diff --git a/packages/angular_devkit/build_angular/src/builders/browser/tests/options/named-chunks_spec.ts b/packages/angular_devkit/build_angular/src/builders/browser/tests/options/named-chunks_spec.ts
index 62a69fa1d0a1..72a58ed1f237 100644
--- a/packages/angular_devkit/build_angular/src/builders/browser/tests/options/named-chunks_spec.ts
+++ b/packages/angular_devkit/build_angular/src/builders/browser/tests/options/named-chunks_spec.ts
@@ -11,7 +11,7 @@ import { BASE_OPTIONS, BROWSER_BUILDER_INFO, describeBuilder } from '../setup';
 
 const MAIN_OUTPUT = 'dist/main.js';
 const NAMED_LAZY_OUTPUT = 'dist/src_lazy-module_ts.js';
-const UNNAMED_LAZY_OUTPUT = 'dist/28.js';
+const UNNAMED_LAZY_OUTPUT = 'dist/358.js';
 
 describeBuilder(buildWebpackBrowser, BROWSER_BUILDER_INFO, (harness) => {
   describe('Option: "namedChunks"', () => {
@@ -61,7 +61,7 @@ describeBuilder(buildWebpackBrowser, BROWSER_BUILDER_INFO, (harness) => {
       const { result } = await harness.executeOnce();
 
       expect(result?.success).toBe(true);
-
+      debugger;
       harness.expectFile(MAIN_OUTPUT).toExist();
       harness.expectFile(NAMED_LAZY_OUTPUT).toNotExist();
       harness.expectFile(UNNAMED_LAZY_OUTPUT).toExist();
diff --git a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/execute-fetch.ts b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/execute-fetch.ts
index ae928b3dbc8d..eb6d1e029793 100644
--- a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/execute-fetch.ts
+++ b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/execute-fetch.ts
@@ -12,7 +12,7 @@ import {
   BuilderHarness,
   BuilderHarnessExecutionOptions,
   BuilderHarnessExecutionResult,
-} from '../../../testing/builder-harness';
+} from '../../../testing';
 
 export async function executeOnceAndFetch<T>(
   harness: BuilderHarness<T>,
diff --git a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/jasmine-helpers.ts b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/jasmine-helpers.ts
index 3bb4438a79df..139fd76c1996 100644
--- a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/jasmine-helpers.ts
+++ b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/jasmine-helpers.ts
@@ -9,7 +9,7 @@
 import { BuilderHandlerFn } from '@angular-devkit/architect';
 import { json } from '@angular-devkit/core';
 import { readFileSync } from 'fs';
-import { JasmineBuilderHarness } from '../../../testing/jasmine-helpers';
+import { JasmineBuilderHarness } from '../../../testing';
 import { host } from '../../../testing/test-utils';
 import { setupApplicationTarget, setupBrowserTarget } from './setup';
 
diff --git a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/options/proxy-config_spec.ts b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/options/proxy-config_spec.ts
index d21507e48f93..f1425104f452 100644
--- a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/options/proxy-config_spec.ts
+++ b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/options/proxy-config_spec.ts
@@ -7,7 +7,7 @@
  */
 
 import { createServer } from 'node:http';
-import { JasmineBuilderHarness } from '../../../../testing/jasmine-helpers';
+import { BuilderHarness } from '../../../../testing';
 import { executeDevServer } from '../../index';
 import { executeOnceAndFetch } from '../execute-fetch';
 import { describeServeBuilder } from '../jasmine-helpers';
@@ -275,7 +275,7 @@ async function createProxyServer() {
 /**
  * Vite specific tests
  */
-function viteOnlyTests(harness: JasmineBuilderHarness<unknown>): void {
+function viteOnlyTests(harness: BuilderHarness<unknown>): void {
   it('proxies support regexp as context', async () => {
     harness.useTarget('serve', {
       ...BASE_OPTIONS,
diff --git a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/setup.ts b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/setup.ts
index 20d0cdba7287..024372bd3e97 100644
--- a/packages/angular_devkit/build_angular/src/builders/dev-server/tests/setup.ts
+++ b/packages/angular_devkit/build_angular/src/builders/dev-server/tests/setup.ts
@@ -8,7 +8,7 @@
 
 import { json } from '@angular-devkit/core';
 import { readFileSync } from 'fs';
-import { BuilderHarness } from '../../../testing/builder-harness';
+import { BuilderHarness } from '../../../testing';
 import { buildApplication } from '../../application';
 import { Schema as AppilicationSchema } from '../../application/schema';
 import {
diff --git a/packages/angular_devkit/build_angular/src/testing/index.ts b/packages/angular_devkit/build_angular/src/testing/index.ts
index 51bcba582bbc..d945d4a5018f 100644
--- a/packages/angular_devkit/build_angular/src/testing/index.ts
+++ b/packages/angular_devkit/build_angular/src/testing/index.ts
@@ -6,5 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-export { BuilderHarnessExecutionOptions, BuilderHarnessExecutionResult } from './builder-harness';
-export { HarnessFileMatchers, describeBuilder } from './jasmine-helpers';
+// TODO: Consider using package.json imports field instead of relative path
+//       after the switch to rules_js.
+export * from '../../../../../modules/testing/builder/src';
diff --git a/packages/angular_devkit/build_angular/src/testing/test-utils.ts b/packages/angular_devkit/build_angular/src/testing/test-utils.ts
index 6ad88f9dce0e..6dca5fb3b5d1 100644
--- a/packages/angular_devkit/build_angular/src/testing/test-utils.ts
+++ b/packages/angular_devkit/build_angular/src/testing/test-utils.ts
@@ -6,170 +6,4 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import { Architect, BuilderOutput, ScheduleOptions, Target } from '@angular-devkit/architect';
-import { WorkspaceNodeModulesArchitectHost } from '@angular-devkit/architect/node';
-import { TestProjectHost, TestingArchitectHost } from '@angular-devkit/architect/testing';
-import { BrowserBuilderOutput } from '@angular-devkit/build-angular';
-import {
-  Path,
-  getSystemPath,
-  join,
-  json,
-  normalize,
-  schema,
-  virtualFs,
-  workspaces,
-} from '@angular-devkit/core';
-import { firstValueFrom } from 'rxjs';
-
-// Default timeout for large specs is 2.5 minutes.
-jasmine.DEFAULT_TIMEOUT_INTERVAL = 150000;
-
-export const workspaceRoot = join(normalize(__dirname), `../../test/hello-world-app/`);
-export const host = new TestProjectHost(workspaceRoot);
-export const outputPath: Path = normalize('dist');
-
-export const browserTargetSpec = { project: 'app', target: 'build' };
-export const devServerTargetSpec = { project: 'app', target: 'serve' };
-export const extractI18nTargetSpec = { project: 'app', target: 'extract-i18n' };
-export const karmaTargetSpec = { project: 'app', target: 'test' };
-export const tslintTargetSpec = { project: 'app', target: 'lint' };
-export const protractorTargetSpec = { project: 'app-e2e', target: 'e2e' };
-
-export async function createArchitect(workspaceRoot: Path) {
-  const registry = new schema.CoreSchemaRegistry();
-  registry.addPostTransform(schema.transforms.addUndefinedDefaults);
-  const workspaceSysPath = getSystemPath(workspaceRoot);
-
-  const { workspace } = await workspaces.readWorkspace(
-    workspaceSysPath,
-    workspaces.createWorkspaceHost(host),
-  );
-  const architectHost = new TestingArchitectHost(
-    workspaceSysPath,
-    workspaceSysPath,
-    new WorkspaceNodeModulesArchitectHost(workspace, workspaceSysPath),
-  );
-  const architect = new Architect(architectHost, registry);
-
-  return {
-    workspace,
-    architectHost,
-    architect,
-  };
-}
-
-export interface BrowserBuildOutput {
-  output: BuilderOutput;
-  files: { [file: string]: Promise<string> };
-}
-
-export async function browserBuild(
-  architect: Architect,
-  host: virtualFs.Host,
-  target: Target,
-  overrides?: json.JsonObject,
-  scheduleOptions?: ScheduleOptions,
-): Promise<BrowserBuildOutput> {
-  const run = await architect.scheduleTarget(target, overrides, scheduleOptions);
-  const output = (await run.result) as BrowserBuilderOutput;
-  expect(output.success).toBe(true);
-
-  if (!output.success) {
-    await run.stop();
-
-    return {
-      output,
-      files: {},
-    };
-  }
-
-  const [{ path }] = output.outputs;
-  expect(path).toBeTruthy();
-  const outputPath = normalize(path);
-
-  const fileNames = await firstValueFrom(host.list(outputPath));
-  const files = fileNames.reduce((acc: { [name: string]: Promise<string> }, path) => {
-    let cache: Promise<string> | null = null;
-    Object.defineProperty(acc, path, {
-      enumerable: true,
-      get() {
-        if (cache) {
-          return cache;
-        }
-        if (!fileNames.includes(path)) {
-          return Promise.reject('No file named ' + path);
-        }
-        cache = firstValueFrom(host.read(join(outputPath, path))).then((content) =>
-          virtualFs.fileBufferToString(content),
-        );
-
-        return cache;
-      },
-    });
-
-    return acc;
-  }, {});
-
-  await run.stop();
-
-  return {
-    output,
-    files,
-  };
-}
-
-export const lazyModuleFiles: { [path: string]: string } = {
-  'src/app/lazy/lazy-routing.module.ts': `
-    import { NgModule } from '@angular/core';
-    import { Routes, RouterModule } from '@angular/router';
-
-    const routes: Routes = [];
-
-    @NgModule({
-      imports: [RouterModule.forChild(routes)],
-      exports: [RouterModule]
-    })
-    export class LazyRoutingModule { }
-  `,
-  'src/app/lazy/lazy.module.ts': `
-    import { NgModule } from '@angular/core';
-    import { CommonModule } from '@angular/common';
-
-    import { LazyRoutingModule } from './lazy-routing.module';
-
-    @NgModule({
-      imports: [
-        CommonModule,
-        LazyRoutingModule
-      ],
-      declarations: []
-    })
-    export class LazyModule { }
-  `,
-};
-
-export const lazyModuleFnImport: { [path: string]: string } = {
-  'src/app/app.module.ts': `
-    import { BrowserModule } from '@angular/platform-browser';
-    import { NgModule } from '@angular/core';
-
-    import { AppComponent } from './app.component';
-    import { RouterModule } from '@angular/router';
-
-    @NgModule({
-      declarations: [
-        AppComponent
-      ],
-      imports: [
-        BrowserModule,
-        RouterModule.forRoot([
-          { path: 'lazy', loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule) }
-        ])
-      ],
-      providers: [],
-      bootstrap: [AppComponent]
-    })
-    export class AppModule { }
-`,
-};
+export * from '../../../../../modules/testing/builder/src';