add unit tests for logger

[codacy-production[bot]]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
:white_check_mark: +42.58% (target: -1.00%)	:white_check_mark: 81.36%

Coverage variation details

| | Coverable lines | Covered lines | Coverage | | ------------- | ------------- | ------------- | ------------- | | Common ancestor commit (bb3bba5f992bc5f793c8a13e3dd65b4d40cc25d5) | 443 | 61 | 13.77% | | | Head commit (d311b031194612022e9e8a405ad58d5265fda6af) | 575 (+132) | 324 (+263) | 56.35% (**+42.58%**) | **Coverage variation** is the difference between the coverage for the head and common ancestor commits of the pull request branch: ` - `

Diff coverage details

| | Coverable lines | Covered lines | Diff coverage | | ------------- | ------------- | ------------- | ------------- | | Pull request (#29) | 59 | 48 | **81.36%** | **Diff coverage** is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: `/ * 100%`

See your quality gate settings    Change summary preferences

_{You may notice some variations in coverage metrics with the latest Coverage engine update. For more details, visit the documentation}