Repository navigation
Angular 21 new unit test builder with Karma and zone.js #32905
Description
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
20
Description
After upgrading from Angular 20 to 21, I ran into NGXXXX errors when running unit tests still with Karma and zone.js.
I found a closed issue and a supposed fix for it, but that did not resolve the issue.
Others experienced the same and implemented workarounds which actually do work: StackOverflow, Reddit.
I found that the solution could be that the angular.json has to be modified to be in line with the new project template like this:
- change
"builder": "@angular/build:karma" to"builder": "@angular/build:unit-test" - add
"runner": "karma" - remove the rest of the properties (according to documentation these derive from the development configuration)
I did not find anything regarding the necessity of this change in the documentation, but if that is the case, it would be wise to mention it and maybe even add a migration schematic.
Also its not clear what is the alternative for "main": "src/test.ts" which contains global test setup. My guess is that the "setupFiles" property would be the successor (like "karmaConfig" became "runnerConfig"), but that is disabled for Karma.
So my question is: Where should I put global test setup with the new "unit-test" builder when using Karma?
Thanks in advance.
Minimal Reproduction
npm test
Exception or Error
Your Environment
Angular CLI : 21.2.5
Node.js : 24.14.0
Package Manager : npm 11.9.0
Operating System : win32 x64
Anything else relevant?
No response
Activity
json-derulo commentedon Apr 9, 2026
I am the author of the linked Stack Overflow question & answer, and I have just updated my answer to include a workaround for the unit-test builder. Please check it out.
szape89 commentedon Apr 10, 2026
@json-derulo My experience is that using the new builder does not require additional setup. Did you have any issues with that?
My intention was to highlight possible documentation and/or migration shortcomings, furthermore to ask about the possibility of global test setup with the new builder.
emilycarter6561-byte commentedon Apr 11, 2026