E2e fixtures

[rosemcc]

Description

This PR introduces the use of fixtures (mocked data) for some of the e2e tests. We have previously been unable to test certain page types, including Funding and Case Study, because they are all SSO protected, and also we have not been able to test certain page elements easily. Intercepting graphql requests and returning mocked data in the response can solve these problems, without having to add functionality for automated login for testing the sso protected page types.

Solution

• Set up fixtures for each of the page types (Cypress Fixtures)
• Use cy.intercept() to access and modify the request and respond with the mocked data, e.g.:
  cy.intercept('POST', Cypress.env('graphql_server'), (req) => { if (hasOperationName(req, 'GetArticleBySlug')) { req.alias = 'gqlGetArticleBySlug'; req.reply({ fixture: 'article' }); } });
• Ref: Cypress working with graphql
• Some of the tests were using '.should('not.be.empty')' - replaced these with '.should('exist')' to ensure that we are checking that the element is actually present in the DOM.
• Reviewed all e2e tests and added tests where certain page elements were not being checked. Most components should now have some tests associated with them.
• Solution works on CI also, by setting the graphql server url as an environment variable which cypress can access.

Screenshots

N/A

Testing

Lots of e2e test changes/additions

Have the changes been checked in the following browsers?

N/A

[Trombach]

Just a few suggestions. Otherwise looks good to me!