I'm trying to use jest in an Angular 13 project for testing. I use jest-preset-angular with @angular-builders/jest.
I use ngx-pipes, which is a library that is not compiled for Angular 13. It works fine during normal Angular build. But in the jest test run it causes the error:
Error: Unexpected value 'NgStringPipesModule2' imported by the module 'DynamicTestModule'. Please add an @NgModule annotation.
Minimal reproduction: https://github.com/dhcode/jest-preset-angular-13-issue
In my actual project I have the same error also with other Angular libraries.
I ran ng serve before, so the ngcc compilation was done before running the tests.
How can I make my tests run and recognize the external libraries, that have been built with an older Angular version?
From the looks of it, ngx-pipes does not yet publish an Ivy distribution and your project still needs ngcc before running the tests.
// package.json
{
"scripts": {
"test": "ngcc && ng test"
}
}
> jest-tests@0.0.0 test
> ngcc && ng test
Processing legacy "View Engine" libraries:
- ngx-pipes [fesm2015/esm2015] (https://github.com/danrevah/ngx-pipes.git)
- ngx-pipes [esm2015/esm2015] (https://github.com/danrevah/ngx-pipes.git)
- ngx-pipes [main/umd] (https://github.com/danrevah/ngx-pipes.git)
Encourage the library authors to publish an Ivy distribution.
PASS src/app/app.component.spec.ts
AppComponent
✓ should create the app (163 ms)
✓ should have as title 'jest-tests' (46 ms)
✓ should render title (44 ms)
✓ should render shortened text (33 ms)
-------------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-------------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
...component.html | 100 | 100 | 100 | 100 |
app.component.ts | 100 | 100 | 100 | 100 |
-------------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 4 passed, 4 total
Snapshots: 0 total
Time: 3.526 s, estimated 5 s
Ran all test suites.