"naive.New" create the root node typed as "*naiveTrie".
I will implement "TestAdd" and "TestGet".
Fix: Create "testTrie" on starting "TestGet".
Verify "exist" and "node.Value()".
Set the value if "node.Value()" returns 0.
Write the test cases for "*naiveTrie.Add" and "*naiveTrie.Get".
"*naiveTrie.Get" returns "false" when the node has already created even if the value is zero.
Write the error message for tests of "*naiveTrie.Add" and "*naiveTrie.Get".
Fix: Set the value if "node.Value()" returns 0 on adding keys in "TestGet".
Fix: Access the child node with "childIndex". Replace "charIndex" with "childIndex".
Merge branch 'feature/test-naivetrie'