Uncomment tests in ManagerTest

[jonasseglare]

Remove comment around unit tests in ManagerTest

Description

The code for the unit tests in ManagerTest.java were commented out. In this pull request, I remove the comment around the tests because the tests run fine.

Fixes #20

Checklist

• My contributions and commit messages follows the style guidelines of this project
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes
• The Pull Request has an informative and human-readable title
• Changes are limited to a single goal (avoid scope creep)
• Code can be automatically merged (no conflicts)
• I confirm that I have read any Contribution guidelines (CONTRIBUTING)
• I confirm that I wrote and/or have the right to submit the contents of my PR, by agreeing to the Developer Certificate of Origin, by adding a 'sign-off' to my commits