Motivation.
The string functions are classes are essential, which are used in many cases. It is important to have unit test and very high code coverage of these objects and methods.

Actions

• In the unit test folder create at least one file to implement unit tests;
• Similar to DemoTest, include the test in the CMakeLists.txt so that it will compile separate executable.
• All test methods of unit test should be documented with short description of the test agenda.

Additional actions
If a bug is found (test failed), there should be a ticket created and the UT code should be included to demonstrate failure.