test(@schematics/angular): centralize jasmine-to-vitest test helper

This commit refactors the test suite for the `jasmine-to-vitest` schematic by centralizing the duplicated `expectTransformation` helper function into a single `test-helpers.ts` file.

This change improves the long-term maintainability of the test suite by:
- Reducing code duplication across multiple spec files.
- Creating a single source of truth for the core test logic, making future updates easier.
- Improving the overall structure and readability of the tests.

Author: clydin

packages/schematics/angular/BUILD.bazel

@@ -72,6 +72,7 @@ ts_project(
         include = ["**/*.ts"],
         exclude = [
             "**/*_spec.ts",
+            "refactor/jasmine-vitest/test-helpers.ts",
             # Also exclude templated files.
             "*/files/**/*.ts",
             "*/other-files/**/*.ts",
@@ -114,6 +115,7 @@ ts_project(
         include = [
             "**/*_spec.ts",
             "utility/test/**/*.ts",
+            "refactor/jasmine-vitest/test-helpers.ts",
         ],
         exclude = [
             # NB: we need to exclude the nested node_modules that is laid out by yarn workspaces

packages/schematics/angular/refactor/jasmine-vitest/test-file-transformer_spec.ts

@@ -6,20 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { logging } from '@angular-devkit/core';
-import { format } from 'prettier';
-import { transformJasmineToVitest } from './test-file-transformer';
-import { RefactorReporter } from './utils/refactor-reporter';
-
-async function expectTransformation(input: string, expected: string): Promise<void> {
-  const logger = new logging.NullLogger();
-  const reporter = new RefactorReporter(logger);
-  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
-  const formattedTransformed = await format(transformed, { parser: 'typescript' });
-  const formattedExpected = await format(expected, { parser: 'typescript' });
-
-  expect(formattedTransformed).toBe(formattedExpected);
-}
+import { expectTransformation } from './test-helpers';
 
 describe('Jasmine to Vitest Transformer', () => {
   describe('Nested Transformations', () => {

packages/schematics/angular/refactor/jasmine-vitest/test-helpers.ts

@@ -0,0 +1,34 @@
+/**
+ * @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.dev/license
+ */
+
+import { logging } from '@angular-devkit/core';
+import { format } from 'prettier';
+import { transformJasmineToVitest } from './test-file-transformer';
+import { RefactorReporter } from './utils/refactor-reporter';
+
+/**
+ * A test helper to run the Jasmine to Vitest transformer on a given code
+ * snippet and compare it to an expected output.
+ *
+ * This function automatically handles the setup of a `RefactorReporter` and
+ * formats both the transformed and expected code using Prettier. This ensures
+ * that test comparisons are consistent and not affected by minor formatting
+ * differences.
+ *
+ * @param input The Jasmine code snippet to be transformed.
+ * @param expected The expected Vitest code snippet after transformation.
+ */
+export async function expectTransformation(input: string, expected: string): Promise<void> {
+  const logger = new logging.NullLogger();
+  const reporter = new RefactorReporter(logger);
+  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
+  const formattedTransformed = await format(transformed, { parser: 'typescript' });
+  const formattedExpected = await format(expected, { parser: 'typescript' });
+
+  expect(formattedTransformed).toBe(formattedExpected);
+}

packages/schematics/angular/refactor/jasmine-vitest/transformers/jasmine-lifecycle_spec.ts

@@ -6,20 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { logging } from '@angular-devkit/core';
-import { format } from 'prettier';
-import { transformJasmineToVitest } from '../test-file-transformer';
-import { RefactorReporter } from '../utils/refactor-reporter';
-
-async function expectTransformation(input: string, expected: string): Promise<void> {
-  const logger = new logging.NullLogger();
-  const reporter = new RefactorReporter(logger);
-  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
-  const formattedTransformed = await format(transformed, { parser: 'typescript' });
-  const formattedExpected = await format(expected, { parser: 'typescript' });
-
-  expect(formattedTransformed).toBe(formattedExpected);
-}
+import { expectTransformation } from '../test-helpers';
 
 describe('Jasmine to Vitest Transformer', () => {
   describe('transformDoneCallback', () => {

packages/schematics/angular/refactor/jasmine-vitest/transformers/jasmine-matcher_spec.ts

@@ -6,20 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { logging } from '@angular-devkit/core';
-import { format } from 'prettier';
-import { transformJasmineToVitest } from '../test-file-transformer';
-import { RefactorReporter } from '../utils/refactor-reporter';
-
-async function expectTransformation(input: string, expected: string): Promise<void> {
-  const logger = new logging.NullLogger();
-  const reporter = new RefactorReporter(logger);
-  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
-  const formattedTransformed = await format(transformed, { parser: 'typescript' });
-  const formattedExpected = await format(expected, { parser: 'typescript' });
-
-  expect(formattedTransformed).toBe(formattedExpected);
-}
+import { expectTransformation } from '../test-helpers';
 
 describe('Jasmine to Vitest Transformer', () => {
   describe('transformAsymmetricMatchers', () => {

packages/schematics/angular/refactor/jasmine-vitest/transformers/jasmine-misc_spec.ts

@@ -6,20 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { logging } from '@angular-devkit/core';
-import { format } from 'prettier';
-import { transformJasmineToVitest } from '../test-file-transformer';
-import { RefactorReporter } from '../utils/refactor-reporter';
-
-async function expectTransformation(input: string, expected: string): Promise<void> {
-  const logger = new logging.NullLogger();
-  const reporter = new RefactorReporter(logger);
-  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
-  const formattedTransformed = await format(transformed, { parser: 'typescript' });
-  const formattedExpected = await format(expected, { parser: 'typescript' });
-
-  expect(formattedTransformed).toBe(formattedExpected);
-}
+import { expectTransformation } from '../test-helpers';
 
 describe('Jasmine to Vitest Transformer', () => {
   describe('transformTimerMocks', () => {

packages/schematics/angular/refactor/jasmine-vitest/transformers/jasmine-spy_spec.ts

@@ -6,20 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { logging } from '@angular-devkit/core';
-import { format } from 'prettier';
-import { transformJasmineToVitest } from '../test-file-transformer';
-import { RefactorReporter } from '../utils/refactor-reporter';
-
-async function expectTransformation(input: string, expected: string): Promise<void> {
-  const logger = new logging.NullLogger();
-  const reporter = new RefactorReporter(logger);
-  const transformed = transformJasmineToVitest('spec.ts', input, reporter);
-  const formattedTransformed = await format(transformed, { parser: 'typescript' });
-  const formattedExpected = await format(expected, { parser: 'typescript' });
-
-  expect(formattedTransformed).toBe(formattedExpected);
-}
+import { expectTransformation } from '../test-helpers';
 
 describe('Jasmine to Vitest Transformer', () => {
   describe('transformSpies', () => {