How can i mock OleDbDataAdapter(query, conn) in FilledDataInDataTable function? Can i? I have no idea how i do with dependency from query and connection string parameters.
Public Class DataTableOfDataFromExportCSV
Private _adp As IOleDbDataAdapter
Public Sub New(iadp As IOleDbDataAdapter)
_adp = iadp
End Sub
Public Function FilledDataInDataTable(query As String, conStr As String) As DataTable
Dim dt As New DataTable
Dim adp = _adp.OleDbDataAdapter(query, conStr)
adp.Fill(dt)
Return dt
End Function
End Class
Implementation
Public Class MyOleDbDataAdapter
Implements IOleDbDataAdapter
Public Function OleDbDataAdapter(query As String, conn As String) As OleDbDataAdapter Implements IOleDbDataAdapter.OleDbDataAdapter
Dim adp As New OleDbDataAdapter(query, conn)
Return adp
End Function
End Class
My Interface
Public Interface IOleDbDataAdapter
Function OleDbDataAdapter(query As String, conn As String) As OleDbDataAdapter
End Interface
How can I mock OleDbDataAdapter
You can't because it is NotInheritable (sealed - c#).
Public NotInheritable Class OleDbDataAdapter
Inherits DbDataAdapter
Implements ICloneable
What we have here is a Leaky Abstraction.
Expose only what is explicitly needed to perform the desired function.
For example
Public Interface IOleDbDataAdapter
Function Fill(query As String, dataTable As DataTable) As Integer
End Interface
That way, implementation details/concerns like OleDbDataAdapter wont cause tight coupling.
Public Class DataTableOfDataFromExportCSV
Private adp As IOleDbDataAdapter
Public Sub New(iadp As IOleDbDataAdapter)
adp = iadp
End Sub
Public Function FilledDataInDataTable(query As String) As DataTable
Dim dt As New DataTable
adp.Fill(query, dt)
Return dt
End Function
End Class
Note the removal of runtime data that can be managed at the composition root when constructing your components' object graphs or after the component has already been constructed.