Imports Xunit Public Class IsogramTests Public Sub Empty_string() Assert.True(IsIsogram("")) End Sub Public Sub Isogram_with_only_lower_case_characters() Assert.True(IsIsogram("isogram")) End Sub Public Sub Word_with_one_duplicated_character() Assert.False(IsIsogram("eleven")) End Sub Public Sub Word_with_one_duplicated_character_from_the_end_of_the_alphabet() Assert.False(IsIsogram("zzyzx")) End Sub Public Sub Longest_reported_english_isogram() Assert.True(IsIsogram("subdermatoglyphic")) End Sub Public Sub Word_with_duplicated_character_in_mixed_case() Assert.False(IsIsogram("Alphabet")) End Sub Public Sub Word_with_duplicated_character_in_mixed_case_lowercase_first() Assert.False(IsIsogram("alphAbet")) End Sub Public Sub Hypothetical_isogrammic_word_with_hyphen() Assert.True(IsIsogram("thumbscrew-japingly")) End Sub Public Sub Hypothetical_word_with_duplicated_character_following_hyphen() Assert.False(IsIsogram("thumbscrew-jappingly")) End Sub Public Sub Isogram_with_duplicated_hyphen() Assert.True(IsIsogram("six-year-old")) End Sub Public Sub Made_up_name_that_is_an_isogram() Assert.True(IsIsogram("Emily Jung Schwartzkopf")) End Sub Public Sub Duplicated_character_in_the_middle() Assert.False(IsIsogram("accentor")) End Sub Public Sub Same_first_and_last_characters() Assert.False(IsIsogram("angola")) End Sub Public Sub Word_with_duplicated_character_and_with_two_hyphens() Assert.False(IsIsogram("up-to-date")) End Sub End Class