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ngMocks.change helps to simulate external changes of a form control. Does not matter whether the declaration of the form control is a mock instance or a real one.

To simulate a change, we need a debug element the form control belongs to, and the desired value for the change.

Let's assume that we have the next template:

<input data-testid="inputControl" [(ngModel)]="value" />

And, we want to simulate a change of the input which would set value to 123.

Then solution may look like that:

// looking for debug element of the inputconst el = ngMocks.find(['data-testid', 'inputControl']);
// simulating changengMocks.change(el, 123);
// assertingexpect(component.value).toEqual(123);

or simply with selectors which are supported by ngMocks.find.

ngMocks.change('input', 123);
ngMocks.change('[data-testid="inputControl"]', 123);
ngMocks.change(['data-testid'], 123);
ngMocks.change(['data-testid', 'inputControl'], 123);


It supports both FormsModule and ReactiveFormsModule.