Add basic example test for MetricsCollector

[kornys]

Description

Add simple example test of using metrics collector in to our examples

close #67

Type of Change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit/integration tests pass locally with my changes

[im-konge]

I think we should maybe apply the checkstyle check for the tests as well -> because it little bit differs with how we are styling the code and the tests.
But something for different PR, thanks for this :)