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"Cannot instantiate cyclic dependency! NgControl"

See original GitHub issue

After struggling for a couple of days with an error on tests when upgrading our project to Angular 10 (and shallow-render), I’ve found the solution in your playground project on stackblitz.

        .provideMock({
          provide: NG_VALUE_ACCESSOR,
          useClass: DefaultValueAccessor,
          multi: true,
        });

This was what was missing from our tests so we don’t get an error like:

		Error: Template parse errors:
		Cannot instantiate cyclic dependency! NgControl (
		  [ERROR ->]<nz-select #selector
		    (ngModelChange)="onChange($event)"
		    (nzBlur)="onTouched()"
		"): ng:///ShallowTestModule/FormControlImplementationEaseComponent.html@1:2
		
		    at syntaxError (/home/ztp/repos/bee/packages/compiler/src/util.ts:108:17)
		    at TemplateParser.Object.<anonymous>.TemplateParser.parse (/home/ztp/repos/bee/packages/compiler/src/template_parser/template_parser.ts:108:13)

I’ve forked your playground project, and upgraded shallow-render to v10.2.0: https://stackblitz.com/edit/github-mpmyc2?file=examples/test.spec.ts

If I delete that provideMock() code from your example/component-with-forms.spec.ts still works, but not when the ngModel is applied to a component that implements ControlValueAccessor, like on the file “test.spec.ts” on my stackblitz instance.

I’m not understanding this completly so several doubts come across my mind:

Is DefaultValueAccessor provided by Angular by default on NG_VALUE_ACCESSOR ?
Should this provideMock() code above be added by shallow-render automatically besides neverMocking(NG_VALUE_ACCESSOR).

Not sure even if these doubts make sense… Hope you got a more clear view on this. Thanks!