Cypress testing pseudo CSS class :before

Is there a way in which I can test the content of the pseudo CSS class for :before on my element with Cypress?

I have seen links documenting:

• Accessing nth-child pseudo element
• Accessing the actual content pseudo class of a normal CSS class

But I have not found anything for CSS classes using the ::before pseudo class.

Imagine the code:

.myClass:before {
  content: "foo-";
}

<div>
  <span class="myClass">Bar</span>
</div>

How could one test that 'foo-' is present?