Bug(transloco): Unknown components wrapped within Transloco structural directive do not throw in unit tests

[joonashak]

Is there an existing issue for this?

• I have searched the existing issues

Which Transloco package(s) are the source of the bug?

Transloco

Is this a regression?

No

Current behavior

Unit testing does not fail on unknown components if a parent component includes the *transloco="let t" structural directive.

Steps to reproduce:

1. Create a component that wraps an unknown component (I used <child>)within a parent that uses Transloco's structural directive (I used <ng-container *transloco="let t">.
2. Unit test the component, using the { errorOnUnknownElements: true } option.
3. The unit test should fail with Error: NG0304: 'child' is not a known element (used in the 'Test1Component' component template).
4. To see the test fail, remove the structural directive. Note that there is no need to actually use the t function anywhere.

You can also reproduce the bug by cloning the linked example repo, running npm ci, and then npm run test1 to run a test that fails correctly, or npm run test2 to run a test where Transloco causes it to pass when it should fail like the first one. Note that the main branch uses Angular 15 because we originally discovered the bug with that version. There is also ng16 branch that implements the same example with Angular 16 and Transloco 6.

Expected behavior

Using errorOnUnknownElements should throw NG0304 even when wrapped in the Transloco structural directive.

Please provide a link to a minimal reproduction of the bug, if you won't provide a link the issue won't be handled.

https://github.com/funidata/ng-unit-test-debug

Transloco Config

No response

Please provide the environment you discovered this bug in

Transloco: 4.2.6 || 6.0.0
Angular: 15.2.9 || 16.2.6
Node: 18.18
Package Manager: npm@9.8.1
OS: macOS 13.5.2

Browser

No response

Additional context

No response

I would like to make a pull request for this bug

No

[joonashak]

Actually, this might be an older problem with Angular itself. See angular/angular#37322 .

If you think this is the case, feel free to close this issue :)

EDIT: On a second thought, maybe not. The linked issue seems to be about missing directives rather than missing components. Might be related though.

[shaharkazaz]

@joonashak Please update the title.

[joonashak]

Sorry, totally missed the title 🙈