Add unit tests and code coverage report

[var77]

Currently we have end to end tests, but they are not very consistent as in some of the tests we depend on time which sometimes fail.

We need to add unit tests for the most smaller units of the code and try to make codecoverage as high as possible, so adding new features won't break any existing functionality.

Also we need to refactor daemon e2e tests to make them more maintainable.

To cover this issue we need:

• have proper unit tests where dependencies for that unit will be mocked,
• code coverage report
• refactored and consistent e2e tests

[var77]

Resolved with #119