Using overrideComponent breaks code coverage when testing with aot: true
Author: cexbrayatCreated Apr 17, 2025Updated Sep 3, 2026
Labelstype: bug/fixfreq1: lowseverity3: brokendevkit/build-angular:karmaarea: @angular/build
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
No response
Description
When using TestBed.overrideComponent to stub a child component, the test code coverage is no longer accurate
Minimal Reproduction
Generate a new app with latest CLI and add a component:
npx @angular/[email protected] new aot-coverage --defaults --no-routing
cd aot-coverage
ng g c userUse app-user in app.html:
<h1>Hello, aot-coverage</h1>
<app-user></app-user>Edit angular.json to add "aot": true in the test section and run:
ng test --no-watch --code-coverageCoverage is 100%
Statements : 100% ( 12/12 )
Branches : 100% ( 11/11 )
Functions : 100% ( 3/3 )
Lines : 100% ( 6/6 )Now, in the app.spec.ts, add in beforeEach:
TestBed.overrideComponent(App, {
remove: {
imports: [User],
},
add: {
imports: [User],
}
});(this happens with a proper stub of course but even removing the import and adding it back works to reproduce the issue)
Run the tests again:
ng test --no-watch --code-coverageCoverage is now inaccurate because the template is not properly covered:
Statements : 58.33% ( 7/12 )
Branches : 90.9% ( 10/11 )
Functions : 66.66% ( 2/3 )
Lines : 66.66% ( 4/6 )Exception or Error
Your Environment
Angular CLI: 20.0.0-next.6
Node: 22.14.0
Package Manager: npm 10.9.0
OS: darwin arm64
Angular: 20.0.0-next.7
... common, compiler, compiler-cli, core, forms
... platform-browser, router
Package Version
------------------------------------------------------
@angular-devkit/architect 0.2000.0-next.6
@angular-devkit/core 20.0.0-next.6
@angular-devkit/schematics 20.0.0-next.6
@angular/build 20.0.0-next.6
@angular/cli 20.0.0-next.6
@schematics/angular 20.0.0-next.6
rxjs 7.8.2
typescript 5.8.3
zone.js 0.15.0Anything else relevant?
No response
Source: angular/angular-cli