Testing And Benchmarking in Visual Basic .NET

Here’s an idiomatic Visual Basic .NET example that demonstrates testing and benchmarking:

Imports System
Imports Microsoft.VisualStudio.TestTools.UnitTesting
Imports System.Diagnostics

Public Module IntegerUtils
    Public Function IntMin(a As Integer, b As Integer) As Integer
        If a < b Then
            Return a
        End If
        Return b
    End Function
End Module

<TestClass>
Public Class IntegerUtilsTests
    <TestMethod>
    Public Sub TestIntMinBasic()
        Dim result As Integer = IntegerUtils.IntMin(2, -2)
        Assert.AreEqual(-2, result, "IntMin(2, -2) should return -2")
    End Sub

    <TestMethod>
    Public Sub TestIntMinTableDriven()
        Dim testCases As (a As Integer, b As Integer, expected As Integer)() = {
            (0, 1, 0),
            (1, 0, 0),
            (2, -2, -2),
            (0, -1, -1),
            (-1, 0, -1)
        }

        For Each testCase In testCases
            Dim result As Integer = IntegerUtils.IntMin(testCase.a, testCase.b)
            Assert.AreEqual(testCase.expected, result, $"IntMin({testCase.a}, {testCase.b}) should return {testCase.expected}")
        Next
    End Sub

    <TestMethod>
    Public Sub BenchmarkIntMin()
        Const iterations As Integer = 1000000
        Dim stopwatch As New Stopwatch()

        stopwatch.Start()
        For i As Integer = 0 To iterations - 1
            IntegerUtils.IntMin(1, 2)
        Next
        stopwatch.Stop()

        Console.WriteLine($"BenchmarkIntMin: {stopwatch.ElapsedMilliseconds} ms for {iterations} iterations")
    End Sub
End Class

This example demonstrates how to create unit tests and a simple benchmark in Visual Basic .NET using the MSTest framework. Here’s a breakdown of the code:

1. We define a simple IntMin function in a module called IntegerUtils.

2. The IntegerUtilsTests class contains our test methods:

   • TestIntMinBasic is a simple test case.
   • TestIntMinTableDriven demonstrates a table-driven test approach.
   • BenchmarkIntMin is a simple benchmark that measures the performance of the IntMin function.

3. We use the <TestClass> attribute to mark our test class and <TestMethod> to mark individual test methods.

4. In the table-driven test, we use a tuple array to define our test cases.

5. The benchmark method uses the Stopwatch class to measure the execution time of multiple iterations.

To run these tests, you would typically use Visual Studio’s Test Explorer or the dotnet test command-line tool. Here’s how you might run the tests from the command line:

dotnet test YourProjectName.vbproj

This will compile your project and run all the tests, providing output similar to:

Test run for YourProjectName.dll (.NETCoreApp,Version=v3.1)
Microsoft (R) Test Execution Command Line Tool Version 16.6.0
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...

A total of 3 test files matched the specified pattern.

Test Run Successful.
Total tests: 3
     Passed: 3
 Total time: 1.5678 Seconds

The benchmark results will be printed to the console as part of the test output.

Note that in Visual Basic .NET, we don’t have a direct equivalent to Go’s built-in benchmarking tool. Instead, we’ve implemented a simple benchmark using the Stopwatch class. For more sophisticated benchmarking, you might consider using a library like BenchmarkDotNet.

This example demonstrates how to write and organize tests in Visual Basic .NET, following common practices in the .NET ecosystem.