Microservices have received a lot of attention. For Zendesk, what are the business consequences of using a monolith? Is this a mono- or multi-repos? Are tests

Microservices have received a lot of attention. For Zendesk, what are the business consequences of using a monolith? Is this a mono- or multi-repos? Are tests simpler? Does the system require lots of special-purpose tooling? Thanks!