Passing information from pytest to cypress for e2e tests using an env var and a test-specific view

conftest.py

import os


def e2e_my_test(db):
    """We assume this fixture is run before launching the cypress spec using the same name."""
    my_object = ...
    # Note: We may have to make this URL relative or replace its domain 
    #   with live_server.url to avoid running into same-origin constraints 
    #   in the browser. Though cypress v12 upwards is fine with that!
    os.environ["MY_DYNAMIC_URL"] = my_object.url

e2e_my_test.cy.js

describe('Test against a dynamic URL', () => {
  it('should visit the dynamic URL', () => {

    const envLookupURL = Cypress.env('apiBaseUrl') + 'e2e/env' + '?env_var=MY_DYNAMIC_URL';

    cy.request({
      method: 'GET',
      url: envLookupURL,
    })
      .then((response) => {
        const dynamicURL = response.body;
        cy.visit(dynamicURL);
      });
  });
});

urls.py

...

if is_testrun():
    urlpatterns.extend(
        [
            # This view takes an env_var GET parameter and returns its value from os.environ.
            re_path(r"^e2e/env$", e2e_env_lookup),
        ]
    )

views.py

@api_view(("GET",))
@permission_classes(())
def e2e_env_lookup(request):
    if not is_testrun():
        raise PermissionDenied()

    env_var = request.GET["env_var"]
    value = os.environ.get(env_var, None)
    return Response(value)