This TDD code seems noisy [closed]

Question

This is my very-first-ever run at TDD. How did I do?

In keeping with Uncle Bob's Three Rules, I wrote every test first, starting in order from the top down as you see here (below). Here's the sequence I used:

1. For each new method in Production I entered the method-name-to-be in Test.
2. I received a compile-time error.
3. I used Visual Studio's error correction feature to generate the method stubs.
4. I built the solution and ran all tests, resulting in a failure on the most recent test.
5. I wrote Production code to cause the failed test to pass.
6. I built the solution and ran all tests, verifying that they all passed.

To tell you the truth, this all seems pretty redundant. As you can see, each of my tests contains code copied from previous tests--I had to do that so the test would run. I tried making functions out of them, so I could chain them together, but that caused Visual Studio to not see the tests.

Certainly there must be a better way. I'd love to know what it is.

Production:

Public Module Main
  Sub Main()
  End Sub

  Function GetSessionType(RemoteHostName As String) As Type
    Return Type.GetTypeFromProgID("Microsoft.Update.Session", RemoteHostName)
  End Function

  Function GetSession(Type As Type) As UpdateSession
    Return Activator.CreateInstance(Type)
  End Function

  Function GetSearcher(Session As UpdateSession) As IUpdateSearcher
    Return Session.CreateUpdateSearcher
  End Function

  Function GetHistoryCount(Searcher As IUpdateSearcher) As Integer
    Return Searcher.GetTotalHistoryCount
  End Function

  Function GetHistory(Searcher As IUpdateSearcher, Count As Integer) As IUpdateHistoryEntryCollection
    Return Searcher.QueryHistory(0, Count)
  End Function

  Function EnumerateHistory(History As IUpdateHistoryEntryCollection, Count As Integer) As Boolean
    Dim oEntry As IUpdateHistoryEntry

    EnumerateHistory = True

    For iIndex = 0 To Count - 1
      Try
        oEntry = History(iIndex)
        Console.WriteLine("Title: {0}{2}Date: {1}", oEntry.Title, oEntry.Date, vbTab)

      Catch ex As Runtime.InteropServices.COMException
        ' For some reason on MyComputer the GetTotalHistoryCount() method  '
        ' call returns a count higher than the existing update count. This '
        ' catch bypasses the resulting IndexOutOfRange COM errors.         '

      Catch ex As Exception
        EnumerateHistory = False

      End Try

    Next
  End Function
End Module

Test:

Imports System.Text
Imports Microsoft.VisualStudio.TestTools.UnitTesting

<TestClass()>
Public Class UpdateHistoryReaderTests
  Private Const REMOTE_HOST_NAME As String = "MyComputer"

  <TestMethod()>
  Public Sub GetSessionTypeTest()
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)

    Assert.IsNotNull(oType)
  End Sub

  <TestMethod()>
  Public Sub GetSessionTest()
    Dim oSession As UpdateSession
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
    oSession = UpdateHistoryReader.Main.GetSession(oType)

    Assert.IsNotNull(oSession)
  End Sub

  <TestMethod()>
  Public Sub GetSearcherTest()
    Dim oSearcher As IUpdateSearcher
    Dim oSession As UpdateSession
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
    oSession = UpdateHistoryReader.Main.GetSession(oType)
    oSearcher = UpdateHistoryReader.Main.GetSearcher(oSession)

    Assert.IsNotNull(oSearcher)
  End Sub

  <TestMethod()>
  Public Sub GetHistoryCountTest()
    Dim oSearcher As IUpdateSearcher
    Dim oSession As UpdateSession
    Dim iCount As Integer
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
    oSession = UpdateHistoryReader.Main.GetSession(oType)
    oSearcher = UpdateHistoryReader.Main.GetSearcher(oSession)
    iCount = UpdateHistoryReader.Main.GetHistoryCount(oSearcher)

    Assert.IsFalse(iCount = 0)
  End Sub

  <TestMethod()>
  Public Sub GetHistoryTest()
    Dim oSearcher As IUpdateSearcher
    Dim oHistory As IUpdateHistoryEntryCollection
    Dim oSession As UpdateSession
    Dim iCount As Integer
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
    oSession = UpdateHistoryReader.Main.GetSession(oType)
    oSearcher = UpdateHistoryReader.Main.GetSearcher(oSession)
    iCount = UpdateHistoryReader.Main.GetHistoryCount(oSearcher)
    oHistory = UpdateHistoryReader.Main.GetHistory(oSearcher, iCount)

    Assert.IsNotNull(oHistory)
  End Sub

  <TestMethod()>
  Public Sub EnumerateHistoryTest()
    Dim oSearcher As IUpdateSearcher
    Dim oHistory As IUpdateHistoryEntryCollection
    Dim oSession As UpdateSession
    Dim lSuccess As Boolean
    Dim iCount As Integer
    Dim oType As Type

    oType = UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
    oSession = UpdateHistoryReader.Main.GetSession(oType)
    oSearcher = UpdateHistoryReader.Main.GetSearcher(oSession)
    iCount = UpdateHistoryReader.Main.GetHistoryCount(oSearcher)
    oHistory = UpdateHistoryReader.Main.GetHistory(oSearcher, iCount)
    lSuccess = UpdateHistoryReader.Main.EnumerateHistory(oHistory, iCount)

    Assert.IsTrue(lSuccess)
  End Sub
End Class

Answer 1

Assert.IsNotNull(oSession) is in general a really weak test. Maybe you want to test anything in the session or the history etc.

Testing Assert.IsTrue(UpdateHistoryReader.Main.EnumerateHistory) is usually also not enough. What if your success return code is buggy. You need to test the operation itself and not only the return code.

Answer 2

Although you cannot chain unit test methods, you can chain private helper methods, called by unit test methods. For example:

  Private Sub GetSessionType() As Type
    Return UpdateHistoryReader.Main.GetSessionType(REMOTE_HOST_NAME)
  End Sub

  <TestMethod()>
  Public Sub GetSessionTypeTest()
    Dim oType As Type

    oType = GetSessionType

    Assert.IsNotNull(oType)
  End Sub

  Private Sub GetSession() As UpdateSession
    Return UpdateHistoryReader.Main.GetSession(GetSessionType)
  End Sub

  <TestMethod()>
  Public Sub GetSessionTest()
    Dim oSession As UpdateSession

    oSession = GetSession

    Assert.IsNotNull(oSession)
  End Sub

And so on.

This program is not a great example of TDD in action, because you don't seem to have a lot of logic there. Your code is just a pipeline of calls, on a single execution path. Normally you would have many possible execution paths, where testing is much more important.