Component testing in Nuxt : "n is not a function" when including plugins

[franck-grenier]

Hello Cypress,
I'm testing my Nuxt Vue components with Cypress and I sometimes need to include plugins when I mount my component.

I do the following:

import UserAvatar from "@components/UserAvatar.vue";
import placeholder from '@plugins/placeholder.js';

describe('UserAvatar.cy.js', () => {
    it('should display placeholder if told so', () => {
        cy.mount(UserAvatar, {
            propsData: {
                user: {
                    "firstName": "Jeanne",
                    "lastName": "Alouin",
                    "profilePictureUrl": "https://somewhereontheweb.com",
                },
                usePlaceholder: true
            },
            extensions: {
                plugins: [placeholder],
            },
        })
        cy.get('[data-test="user-avatar_img"]').should('have.attr', 'src', 'https://somewhereontheweb.com').not()
        cy.get('[data-test="user-avatar_img"]').should('have.attr', 'alt', 'Photo de profil')
    })
})

My placeholder plugin is:

export default (context, inject) => {
    inject('placeholderProfilePicture', placeholderProfilePicture);
    inject('placeholderDocumentThumbnail', placeholderDocumentThumbnail);
};

When I include the plugin in the mount method call, I get an error on inject instructions :

TypeError: t is not a function

It looks like the Nuxt inject function is unknown in the Cypress component testing context.

What should I do ? I can't find any documentation about this...

Thanks for your help