Mocking DB calls

Hi
Here's my suggestion:
Refactor the code that returns DataRow into a separate method:

Public Function GetDataRow(ByVal artistId As Long, ByVal recDataSet As RecordingDataSet) As DataRow()
  Me.command.Parameters("@id").Value = artistId
    Me.adapter.Fill(recDataSet, recDataSet.Artists.TableName)
    Dim rows() As DataRow = recDataSet.Artists.Select(String.Format("id={0}", artistId)) 
   Return rows
End Function

This will let you fake easily just what you need which is the DataSet object.
Than your test will look something like this:

    <TestMethod> Public Sub FindById_Test()
        Dim mockDataRow As RecorderManager.CreateObject(Of DataRow)
        Dim ret() As DataRow = {mockDataRow.Object}

        Using recorder As New RecordExpectations
            Dim mock As New ClassUnderTest()
            recorder.ExpectAndReturn(mock.GetDataRow, ret)
        End Using

        Dim classUnderTest As New ClassUnderTest()
        classUnderTest.FindById(1, New RecordingDataSet())
    End Sub

And just to taste the future - The next version of Typemock Isolator that will be out next week
will include special API for VB. Here's how the test will look like in the next version:

<TestMethod> Public Sub FindById_Test2()
   'Create our return value
   Dim fake As DataRow = FakeInstance(Of DataRow)()
   Dim ret() As DataRow = {fake}

   Dim classUnderTest As New SomeNameSpace.ClassUnderTest()
   ' Stubbing the GetDataRow method. When called the method will return the array we created
   Using TheseCalls.WillReturn(ret)
      classUnderTest.GetDataRow()
   End Using

   Dim artist As RecordingDataSet.Artist = classUnderTest.FindById(1, New SomeNameSpace.RecordingDataSet())
   'Asserting that FindById works as expected
   Assert.IsNotNull(artist)
End Sub

Hope it helps :)