public void MakeOptional_AlreadyOptional_ReturnsExpected()
{
var innerReader = new ColumnIndexValueReader(1);
OneToOneMap <string> propertyMap = Map(t => t.Value).WithReader(innerReader);
Assert.Same(propertyMap, propertyMap.MakeOptional());
Assert.True(propertyMap.Optional);
Assert.Same(propertyMap, propertyMap.MakeOptional());
Assert.True(propertyMap.Optional);
Assert.Same(innerReader, propertyMap.CellReader);
}
