Using AI Copilot to add NI Number validation and tests to an existing VB Net Project
2 min read - 27 Feb, 2025aivisual studioI have been asked to add a NI Number to one of our current VB .Net applications, and I though I would add some validation to the form, this seems like a great task for AI Copilot.
give me the vb code to validate a ni number
And it responded:
Public Function IsValidNINumber(niNumber As String) As Boolean
' Regular expression pattern for NI number
Dim pattern As String = "^(?!BG|GB|KN|NK|NT|TN|ZZ)(?:[A-CEGHJ-PR-TW-Z][A-CEGHJ-NPR-TW-Z])\d{6}[A-D]$"
Dim regex As New System.Text.RegularExpressions.Regex(pattern)
' Check if the NI number matches the pattern
Return regex.IsMatch(niNumber)
End FunctionI don't like trusting it blindly, so a quick check on google reveals:
What makes an NI number invalid?
- The first two letters cannot be D, F, I, Q, U, or V.
- The second letter cannot be O.
- The prefixes BG, GB, NK, KN, TN, NT, and ZZ are not allocated.
I also asked Copilot:
now give me a list of test cases
Also ran this through a validator:
The AI event went as far as creating the Unit Tests:
<Test>
Public Sub IsValidNINumber_ValidNI_ReturnsTrue()
Dim result As Boolean = frm.IsValidNINumber("AB123456C")
Assert.IsTrue(result)
End Sub
<Test>
Public Sub IsValidNINumber_InvalidNI_ReturnsFalse()
Dim result As Boolean = frm.IsValidNINumber("123456AB")
Assert.IsFalse(result)
End Sub
<Test>
Public Sub IsValidNINumber_DisallowedPrefix_ReturnsFalse()
Dim result As Boolean = frm.IsValidNINumber("BG123456C")
Assert.IsFalse(result)
End Sub
<Test>
Public Sub IsValidNINumber_MissingFinalLetter_ReturnsFalse()
Dim result As Boolean = frm.IsValidNINumber("AB123456")
Assert.IsFalse(result)
End Sub
<Test>
Public Sub IsValidNINumber_ExtraCharacters_ReturnsFalse()
Dim result As Boolean = frm.IsValidNINumber("AB123456CD")
Assert.IsFalse(result)
End SubAnd there it is, this post took way longer to write than it did to use AI to add code to my project.
