public void MusicSelection_MethodSetItemNumber_FieldItemNumber_LowerCaseSetCorrectly()
{
//Arrange
Contributor composer = new Contributor(new Name("David", "", "Haas"), "Composer");
MusicSelectionMock myMusicSelection =
new MusicSelectionMock("9999991e810c19729de860ea", "507f191e810c19729de860ea", "Blest Are They", composer);
//Act
myMusicSelection.setItemNumber("ABC123");
//Assert
Assert.AreEqual("abc123", myMusicSelection.ItemNumber_LowerCase);
}