PP-9916 Change test card number in Stripe test accounts

Add Cypresss test to check 'Mock card' screen shows correct card number for non Stripe accounts.

test/cypress/integration/demo-payment/mock-cards.cy.js

@@ -0,0 +1,36 @@
+const userStubs = require('../../stubs/user-stubs')
+const gatewayAccountStubs = require('../../stubs/gateway-account-stubs')
+const transactionStubs = require('../../stubs/transaction-stubs')
+
+const userExternalId = 'cd0fa54cf3b7408a80ae2f1b93e7c16e'
+const gatewayAccountId = '42'
+const gatewayAccountExternalId = 'a-valid-external-id'
+
+describe('Show Mock cards screen', () => {
+  beforeEach(() => {
+    cy.task('setupStubs', [
+      userStubs.getUserSuccess({ gatewayAccountId, userExternalId }),
+      gatewayAccountStubs.getGatewayAccountByExternalIdSuccess({
+        gatewayAccountId,
+        gatewayAccountExternalId,
+        paymentProvider: 'sandbox'
+      }),
+      transactionStubs.getTransactionsSummarySuccess()
+    ])
+  })
+
+  it('should load the mock cards page and show non stripe card', () => {
+    cy.setEncryptedCookies(userExternalId)
+    cy.visit(`/account/${gatewayAccountExternalId}/dashboard`)
+    cy.get('a').contains('Make a demo payment').click()
+    cy.get('h1').should('have.text', 'Make a demo payment')
+
+    cy.get('#payment-description').contains('An example payment description')
+    cy.get('#payment-amount').contains('£20.00')
+
+    cy.log('Continue to Mock Cards page')
+    cy.get('a').contains('Continue').click()
+    cy.get('h1').should('have.text', 'Mock card numbers')
+    cy.get('p').contains(/^4000056655665556/)
+  })
+})