server not exposed in tests for projects generated with mongoose template

[laurentmor]

tools used
NPM 7.5.4
Node 16.9.1
Typescript 4.2.4
fastify-gen 0.3.0
Jest 26.6.3
Issue description
Using the generated code out of the box during test execution, we encounter the following error:

I suspect that the following snippet is causing this:

Server startup code is as follow:

Despite the fastify server object being returned by the exported init() method, it looks like fastify server instance and methods are not exposed to test

** Expected behavior**
Tests should work out of the box just fine

Am I doing something wrong ?