test: Added compareString function

[mertcanaltin]

The compareString function is a utility function used for comparing two strings and reporting any differences as test failures. It takes four parameters:

• t is the testing.T object, which is used for reporting test failures.
• expected is the expected string value.
• actual is the actual string value.
• message is an additional message to be included in the failure message.

If the expected and actual strings are not equal, the function uses the t.Errorf function to report a test failure, including the expected and actual values, along with the additional message.

issue: #4
fyi @anonrig @lemire

[lemire]

Merging