Mockolate

Mockolate is a modern, strongly-typed, AOT-compatible mocking library for .NET, powered by source generators. It enables fast, compile-time validated mocking with .NET Standard 2.0, .NET 8, .NET 10 and .NET Framework 4.8.

• Source generator-based: No runtime proxy generation.
• Fast: Direct dispatch with no reflection or dynamic proxies.
• Strongly-typed: Compile-time safety and IntelliSense support.
• AOT compatible: Works with Native AOT and trimming.
• Modern C#: First-class support for ref structs, static interface members, and current language features.

Why Mockolate

	Reflection-based mocks (Moq, NSubstitute, …)	Mockolate
AOT / trimming	not supported	supported
Validation	runtime exceptions	analyzers + compile errors
Setup API	Expression<Func<…>> trees	regular method calls
Hot path	dynamic-proxy dispatch	direct dispatch

For side-by-side setup, usage, and verification syntax against Moq, NSubstitute, and FakeItEasy, see the full code comparison; for performance, see the benchmarks.

Already on Moq or NSubstitute? The companion package Mockolate.Migration ships analyzers and code fixers that translate common Moq and NSubstitute patterns to Mockolate syntax in-place: point it at an existing test project and apply the suggested fixes.

Installation

Install the .NET 10 SDK. Mockolate leverages C# 14 extension members (the projects can still target any supported framework). Then add the package:

dotnet add package Mockolate

Quick Start

using Mockolate;

public interface IChocolateDispenser
{
    bool Dispense(string type, int amount);
}

// Create a mock
IChocolateDispenser sut = IChocolateDispenser.CreateMock();

// Setup: Dispense returns true for any Dark chocolate request
sut.Mock.Setup.Dispense("Dark", It.IsAny<int>()).Returns(true);

// Act
bool success = sut.Dispense("Dark", 4);

// Verify
sut.Mock.Verify.Dispense("Dark", It.IsAny<int>()).Once();

Documentation

Full reference docs at docs.testably.org/Mockolate:

• Create mocks
• Setup: properties, methods, indexers, parameter matching
• Mock events
• Verify interactions
• Advanced features: protected members, static interface members, callbacks, monitors, scenarios, unexpected-interaction checks
• Special types: HttpClient, delegates