* x = x + "" => x += ""
* pre-allocating slice with known size
* added t.Helper() methods in test helpers
* complex if-else conditions replaced by switches
* errors should be checked using error.Is() instead of ==
* function parameter should start with lower case letter
* removed unnecessary type definition
* variable/label naming convention: camelCase instead of snake_case
Directories: 0755 (5 - group and other can read cd into the directory and read it's content)
Files: 0644 (4 - group and other can only read the created files)
Tests files: 0777
