Unit Test using Vitest for service class that inject HttpClient will hit JIT Compilation fail error #32095

import { HttpClient } from '@angular/common/http';
import { inject, Injectable } from "@angular/core";

@Injectable({ providedIn: 'root', useFactory: () => new ChildService() })
export abstract class BaseService {
  abstract foo(): string;
}

@Injectable({ providedIn: 'root' })
export class ChildService extends BaseService {

  // Comment the following injection to see the error disappear
  protected httpClient = inject(HttpClient);

  override foo(): string {
    return 'bar';
  }
}

stderr | projects/my-lib/ui/my-lib/my-lib.spec.ts
JIT compilation failed for injectable [class PlatformLocation]

                                                                                                                                                  
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Suites 1 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
                                                                                                                                                  
 FAIL   my-lib  projects/my-lib/ui/my-lib/my-lib.spec.ts [ projects/my-lib/ui/my-lib/my-lib.spec.ts ]                                             
Error: The injectable 'PlatformLocation' needs to be compiled using the JIT compiler, but '@angular/compiler' is not available.                   
                                                                                                                                                  
The injectable is part of a library that has been partially compiled.                                                                             
However, the Angular Linker has not processed the library such that JIT compilation is used as fallback.

Ideally, the library is processed using the Angular Linker to become fully AOT compiled.
Alternatively, the JIT compiler should be loaded by bootstrapping using '@angular/platform-browser-dynamic' or '@angular/platform-server',        
or manually provide the compiler with 'import "@angular/compiler";' before bootstrapping.
 ❯ getCompilerFacade node_modules/.pnpm/@angular+core@21.0.3_@angular+compiler@21.0.3_rxjs@7.8.2/node_modules/@angular/core/fesm2022/_debug_node-chunk.mjs:143:11
 ❯ Module.ɵɵngDeclareFactory node_modules/.pnpm/@angular+core@21.0.3_@angular+compiler@21.0.3_rxjs@7.8.2/node_modules/@angular/core/fesm2022/core.mjs:2594:20
 ❯ Function.<static_initializer> node_modules/.pnpm/@angular+common@21.0.3_@ang_e9b7452ef12a5f71d197dda1c8d449ff/node_modules/@angular/common/fesm2022/_platform_location-chunk.mjs:23:20
 ❯ node_modules/.pnpm/@angular+common@21.0.3_@ang_e9b7452ef12a5f71d197dda1c8d449ff/node_modules/@angular/common/fesm2022/_platform_location-chunk.mjs:17:1
 ❯ projects/my-lib/core/my-service/my-service.ts:1:1

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯


 Test Files  1 failed (1)
      Tests  no tests
   Start at  11:36:33
   Duration  986ms (transform 31ms, setup 0ms, import 0ms, tests 0ms, environment 625ms)

Angular CLI       : 21.0.2
Angular           : 21.0.3
Node.js           : 22.16.0
Package Manager   : pnpm 10.23.0
Operating System  : win32 x64

┌───────────────────────────┬───────────────────┬───────────────────┐
│ Package                   │ Installed Version │ Requested Version │
├───────────────────────────┼───────────────────┼───────────────────┤
│ @angular/build            │ 21.0.2            │ ^21.0.2           │
│ @angular/cli              │ 21.0.2            │ ^21.0.2           │
│ @angular/common           │ 21.0.3            │ ^21.0.0           │
│ @angular/compiler         │ 21.0.3            │ ^21.0.0           │
│ @angular/compiler-cli     │ 21.0.3            │ ^21.0.0           │
│ @angular/core             │ 21.0.3            │ ^21.0.0           │
│ @angular/forms            │ 21.0.3            │ ^21.0.0           │
│ @angular/platform-browser │ 21.0.3            │ ^21.0.0           │
│ @angular/router           │ 21.0.3            │ ^21.0.0           │
│ ng-packagr                │ 21.0.0            │ ^21.0.0           │
│ rxjs                      │ 7.8.2             │ ~7.8.0            │
│ typescript                │ 5.9.3             │ ~5.9.2            │
│ vitest                    │ 4.0.15            │ ^4.0.8            │
└───────────────────────────┴───────────────────┴───────────────────┘