@angular/builder:unit-test does not serve static assets at the correct output path

[wein2011]

Command

test

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

21.0.0-next.2 (bug shows up with 21.0.0-next.3)

Description

When testing the new Vitest unit-test features in 21.0.0-next.6, I noticed a new issue when serving static assets.

One of the static assets is 'src/assets/image/add-0.0.1.svg'.

The angular.json configuration is:

"build": {
  ...
  "assets": ["src/assets"],
  ...
}

or

"build": {
  ...
  "assets": [{
    "glob": "**/*",
    "input": "src/assets",
    "output": "/assets"
  }],
  ...
}

When serving the application with 'ng server', the static assets is served correctly at:

http://localhost:4200/assets/image/add-0.0.1.svg

However, when serving the application with 'ng test --browsers Chromium --watch', the static assets is NOT served at:

http://localhost:63315/assets/image/add-0.0.1.svg

Instead the static assets is only served at:

http://localhost:63315/src/assets/image/add-0.0.1.svg

It seems like that the unit-test build does not take the complete 'assets' configuration into account.

This still worked in 21.0.0-next.2 as well as 20.2.0.

Minimal Reproduction

1. Add a static assets such as 'src/assets/image/add-0.0.1.svg'.

2. Add the assets configuration to angular.json:

"build": {
  ...
  "assets": ["src/assets"],
  ...
}

3. Run the application with 'ng test --browsers Chromium --watch'.

4. Check if static assets is served at:

http://localhost:63315/assets/image/add-0.0.1.svg

Exception or Error

Your Environment

Angular CLI       : 21.0.0-next.6
Node.js           : 22.18.0
Package Manager   : npm 10.9.3
Operating System  : win32 x64

┌───────────────────────────┬───────────────┐
│ Package                   │ Version       │
├───────────────────────────┼───────────────┤
│ @angular/build            │ 21.0.0-next.6 │
│ @angular/cli              │ 21.0.0-next.6 │
│ @angular/common           │ 21.0.0-next.6 │
│ @angular/compiler         │ 21.0.0-next.6 │
│ @angular/compiler-cli     │ 21.0.0-next.6 │
│ @angular/core             │ 21.0.0-next.6 │
│ @angular/forms            │ 21.0.0-next.6 │
│ @angular/platform-browser │ 21.0.0-next.6 │
│ @angular/router           │ 21.0.0-next.6 │
│ rxjs                      │ 7.8.2         │
│ typescript                │ 5.9.3         │
└───────────────────────────┴───────────────┘

Anything else relevant?

No response

[clydin]

Unfortunately, we are unable to reproduce the issue as described. Please provide a minimal reproduction demonstrating the problem so that we may further assist.

[wein2011]

I attached a minimal reproduction demo (simplified 10/5/2025).

v21.0.0-next.6.zip

1. Unzip the file
2. Open Visual Studio Code on Windows
3. Run npm install (this installs v21.0.0-next.6)
4. Run npm run test-file
5. After Chromium opens Vitest tab, open another tab on Chromium
6. On the second tab enter the URL: http://localhost:63315/src/assets/image/add-0.0.1.svg
7. You will see the + svg

Based on the angular.json, the correct URL for the test environment should have been: http://localhost:63315/assets/image/add-0.0.1.svg. It should not require the src folder.

You can verify the correct URL with the development environment:

1. Run npm start
2. Open Chrome tab and enter the URL: http://localhost:4200/assets/image/add-0.0.1.svg
3. You will see the + svg (no need for the src folder)

If you change back to v21.0.0-next.2, it works correctly and consistently without a src folder for both the test environment (npm run test) and the development environment (npm run start):

1. http://localhost:63315/assets/image/add-0.0.1.svg
2. http://localhost:4200/assets/image/add-0.0.1.svg

The behavior is the same for the angular.json configurations:

"build": {
  ...
  "assets": ["src/assets"],
  ...
}

or

"build": {
  ...
  "assets": [{
    "glob": "**/*",
    "input": "src/assets",
    "output": "/assets"
  }],
  ...
}