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How to use the MTP adapter

Conjecture.TestingPlatform is a native Microsoft Testing Platform (MTP) adapter. The test project compiles to a self-contained executable — no xUnit, NUnit, or MSTest runner needed.

When to choose MTP

  • .NET 10+ greenfield projects — MTP is the default going forward and requires no framework dependency.
  • Minimal dependencies — just Conjecture.TestingPlatform; no third-party test framework.
  • Framework-agnostic pipelines — no runner packages, no .runsettings, no adapter DLLs.

If you have an existing test suite in xUnit, NUnit, or MSTest, stay with the corresponding adapter. Conjecture's [Property] API is identical across all adapters.

Project setup

Create a new class library, then add Conjecture.TestingPlatform:

dotnet new classlib -n MyProject.Tests
cd MyProject.Tests
dotnet add package Conjecture.TestingPlatform

Edit the generated .csproj to set OutputType=Exe:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Conjecture.TestingPlatform" Version="*" />
  </ItemGroup>
</Project>

The package supplies the entry point — no Program.cs needed in your project.

Minimal working example

using Conjecture.Core;
using Conjecture.TestingPlatform;

public class MathTests
{
    [Property]
    public bool Addition_is_commutative(int a, int b) => a + b == b + a;

    [Property(MaxExamples = 500)]
    public void Abs_is_non_negative(int value)
    {
        Assume.That(value != int.MinValue);
        if (Math.Abs(value) < 0)
        {
            throw new Exception("Negative abs value");
        }
    }
}

Run with:

dotnet test

Each [Property] method runs against 100 randomly generated inputs by default. A failure shows the shrunk counterexample.

Configure per-test behaviour

Set [Property] attribute properties to control individual test runs:

[Property(MaxExamples = 500, DeadlineMs = 200)]
public bool Reverse_preserves_length(List<int> xs) =>
    xs.AsEnumerable().Reverse().Count() == xs.Count;

[Property(Seed = 42UL, Database = false)]
public void Deterministic_property(int value)
{
    Assert.True(value < int.MaxValue);
}

[Property(ExportReproductionOnFailure = true, ReproductionOutputPath = "failures/")]
public bool Serialisation_roundtrips(string input) =>
    Deserialise(Serialise(input)) == input;

For the full list of properties and their defaults, see Attributes reference.

To apply defaults across the whole assembly, use [assembly: ConjectureSettings(...)]:

[assembly: ConjectureSettings(MaxExamples = 500, Database = false)]
Note

The --conjecture-seed and --conjecture-max-examples CLI flags override the corresponding attribute values for every property in the run. See CLI options below.

CLI options

Two CLI flags override settings globally for all properties in the run:

Option Description
--conjecture-seed <ulong> Fix a seed for deterministic replay across all properties
--conjecture-max-examples <int> Override MaxExamples for all properties

Pass them after -- so dotnet test forwards them to the executable:

dotnet test -- --conjecture-seed 42
dotnet test -- --conjecture-max-examples 1000

TRX reports

TRX output is supported out of the box — no extra configuration:

dotnet test --report-trx

Failed test nodes include the Conjecture counterexample, so the TRX captures the minimal failing input alongside the failure message.

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