How can I pass an array as Input() from the component template?

You need to wrap the property with [] otherwise it is not processed by Angular at all:

[data]="[1, 2, 'test']"

Your example seems to set data from inside the component. This is not how binding works. What you can do with your component is <my-component [data]="[1, 2, 'test']"></my-component> to pass data from the outside to your component.