public void Find_Unique_Words_And_Their_Count()
{
string[] listOfWords = new string[] { "pen", "pencil", "eraser", "pen" };
var hashMap = HashMap.FindUniqueWordsAndTheirCount(listOfWords);
Assert.Equal(2, hashMap["pen"]);
Assert.Equal(1, hashMap["pencil"]);
Assert.Equal(1, hashMap["eraser"]);
}