This question is related to this question. I have several models stored in a collection. I loop through the collection and validate each field. Based on the input, a field can either be successful, have an error or a warning. Is it safe to unit test each decorator and assert that the type of object returned is what you would expect based on the given input? I could perhaps see this being an issue for a language with function return types since my validation function can return one of 3 types.

This is the code I'm fiddling with:

<!-- #include file = "../lib/Collection.asp" -->

<style type="text/css">

td { padding: 4px; }

td.error 
{
    background: #F00F00;
}

td.warning 
{
    background: #FC0;
}

</style>

<%

Class UserModel
    Private m_Name
    Private m_Age
    Private m_Height

    Public Property Let Name(value)
        m_Name = value
    End Property

    Public Property Get Name()
        Name = m_Name
    End Property

    Public Property Let Age(value)
        m_Age = value
    End Property

    Public Property Get Age()
        Age = m_Age
    End Property

    Public Property Let Height(value)
        m_Height = value
    End Property

    Public Property Get Height()
        Height = m_Height
    End Property
End Class

Class NameValidation
    Private m_Name

    Public Function Init(name)
        m_Name = name
    End Function

    Public Function Validate()
        Dim validationObject

        If Len(m_Name) < 5 Then
            Set validationObject = New ValidationError
        Else
            Set validationObject = New ValidationSuccess
        End If

        validationObject.CellValue = m_Name

        Set Validate = validationObject
    End Function
End Class

Class AgeValidation
    Private m_Age

    Public Function Init(age)
        m_Age = age
    End Function

    Public Function Validate()
        Dim validationObject

        If m_Age < 18 Then
            Set validationObject = New ValidationError
        ElseIf m_Age = 18 Then
            Set validationObject = New ValidationWarning
        Else
            Set validationObject = New ValidationSuccess
        End If

        validationObject.CellValue = m_Age

        Set Validate = validationObject
    End Function
End Class

Class HeightValidation
    Private m_Height

    Public Function Init(height)
        m_Height = height
    End Function

    Public Function Validate()
        Dim validationObject

        If m_Height > 400 Then
            Set validationObject = New ValidationError
        ElseIf m_Height = 324 Then
            Set validationObject = New ValidationWarning
        Else
            Set validationObject = New ValidationSuccess
        End If

        validationObject.CellValue = m_Height

        Set Validate = validationObject
    End Function
End Class

Class ValidationError
    Private m_CSSClass
    Private m_CellValue

    Public Property Get CSSClass()
        CSSClass = "error"
    End Property

    Public Property Let CellValue(value)
        m_CellValue = value
    End Property

    Public Property Get CellValue()
        CellValue = m_CellValue
    End Property
End Class

Class ValidationWarning
    Private m_CSSClass
    Private m_CellValue

    Public Property Get CSSClass()
        CSSClass = "warning"
    End Property

    Public Property Let CellValue(value)
        m_CellValue = value
    End Property

    Public Property Get CellValue()
        CellValue = m_CellValue
    End Property
End Class

Class ValidationSuccess
    Private m_CSSClass
    Private m_CellValue

    Public Property Get CSSClass()
        CSSClass = ""
    End Property

    Public Property Let CellValue(value)
        m_CellValue = value
    End Property

    Public Property Get CellValue()
        CellValue = m_CellValue
    End Property
End Class

Class ModelValidator
    Public Function ValidateModel(model)
        Dim modelValidation : Set modelValidation = New CollectionClass

        ' Validate name
        Dim name : Set name = New NameValidation
        name.Init model.Name
        modelValidation.Add name

        ' Validate age
        Dim age : Set age = New AgeValidation
        age.Init model.Age
        modelValidation.Add age

        ' Validate height
        Dim height : Set height = New HeightValidation
        height.Init model.Height
        modelValidation.Add height

        Dim validatedProperties : Set validatedProperties = New CollectionClass
        Dim modelVal
        For Each modelVal In modelValidation.Items()
            validatedProperties.Add modelVal.Validate()
        Next

        Set ValidateModel = validatedProperties
    End Function
End Class

Dim modelCollection : Set modelCollection = New CollectionClass

Dim user1 : Set user1 = New UserModel
user1.Name = "Mike"
user1.Age = 12
user1.Height = 32
modelCollection.Add user1

Dim user2 : Set user2 = New UserModel
user2.Name = "Phil"
user2.Age = 18
user2.Height = 432
modelCollection.Add user2

Dim user3 : Set user3 = New UserModel
user3.Name = "Michele"
user3.Age = 32
user3.Height = 324
modelCollection.Add user3

' Validate all models in the collection
Dim modelValue
Dim validatedModels : Set validatedModels = New CollectionClass
For Each modelValue In modelCollection.Items()
    Dim objModelValidator : Set objModelValidator = New ModelValidator
    validatedModels.Add objModelValidator.ValidateModel(modelValue)
Next

%>

<table>
    <tr>
        <td>Name</td>
        <td>Age</td>
        <td>Height</td>
    </tr>
    <%

    Dim r, c
    For Each r In validatedModels.Items()
        %><tr><%
        For Each c In r.Items()
            %><td class="<%= c.CSSClass %>"><%= c.CellValue %></td><%        
        Next
        %></tr><%
    Next

    %>
</table>

Thank you.