[Milestone] Tests refactoring

[kuzdogan]

The state of the server tests is quite messy. The server is mainly tested by one testfile with ~ 2000 lines. We would like to refactor the tests for improved readability and maintainability. Furthermore, since the tests are mainly integration tests, we might want to add some unit testing. We identified a few more improvements of the tests as in the following list:

Tasks

Beta Give feedback

1. Run etherscan-instances tests nightly on staging #1356
   tests +1
   
2. Add TypeScript to server tests #1373
   +0
   
3. Split the server.js test file #1357
   +0
   
4. Mock Etherscan calls inside the etherscan.js tests #1358
   +0
   
5. Check some of the older CI runs to see if there are flaky tests and ideally fix the flakiness #1359
   +0
   
6. Check why the codecov is not showing individual file coverages #1360
   +0
   
7. Use mocha instead of ava in packages as test runner #1369
   +0
   
8. Replace Ganache in server tests because of deprecation #1382
   +0
   

The tasklist is only a first starting point at the moment. We will probably want to improve the tests further for this milestone.