With Cypress, you can easily create tests for your modern web applications, debug them visually, and automatically run them in your continuous integration builds.

Cypress Community

You need to speak to a front-end dev.  Find an element on the page you can assert on to get the cypress code to wait for it before continuing.

e.g. if you had a spinning icon on the page for 'loading' under SPA it might look something like 
```js
// wait for SPA to load - when loading spinner disappears
cy.get('.loading')
          .should('not.exist')
```

Then after this you can do your login test