Imposter 0.1.4

.NET Standard 2.0

dotnet add package Imposter --version 0.1.4

NuGet\Install-Package Imposter -Version 0.1.4

This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.

<PackageReference Include="Imposter" Version="0.1.4" />

For projects that support PackageReference, copy this XML node into the project file to reference the package.

<PackageVersion Include="Imposter" Version="0.1.4" />
                    

                            Directory.Packages.props

<PackageReference Include="Imposter" />
                    

                            Project file

For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.

paket add Imposter --version 0.1.4

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

#r "nuget: Imposter, 0.1.4"

#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.

#:package Imposter@0.1.4

#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.

#addin nuget:?package=Imposter&version=0.1.4
                    

                            Install as a Cake Addin

#tool nuget:?package=Imposter&version=0.1.4
                    

                            Install as a Cake Tool

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

<p align="center"> The Fastest and Most Memory-Efficient Mocking Library </p>

Visit the Docs for more information

🚀 Quick Start

Add nuget package reference:

dotnet add package Imposter

Pick an interface or non-sealed class that you would like to generate an imposter for.

Say we have a below interface


namespace Application.Domain;

public interface ICalculator
{
    int Add(int a, int b);
}

Use [GenerateImposter] attribute in your tests project, this will generate an imoster

[assembly: GenerateImposter(typeof(Application.Domain.ICalculator))]

Then use can use the generated imposter in your tests

using System.Threading.Tasks;
using Imposter.Abstractions;

// c# 14
var imposter = ICalculator.Imposter();

// c# 9 - 13
// var imposter = new ICalculatorImposter();

imposter.Add(Arg<int>.Any(), Arg<int>.Any())
    .Returns(1)
    .Then()
    .Returns(2);

var calculator = imposter.Instance();

calculator.Add(1, 2); // 1
calculator.Add(1, 2); // 2

Learn more: https://themidnightgospel.github.io/Imposter/

✨ Feature-Rich

⏱️ Benchmark

We benchmarked the simple method-impersonation scenario: we set up a Square method to return input * input and ran it for 1, 10, 100, and 1000 iterations.

public interface ICalculator
{
    int Square(int input);
}

Mean execution time

Method	Iteration	Mean
Moq	1	69,346.1 ns
NSubstitute	1	1,976.2 ns
Imposter	1	194.3 ns
Moq	10	686,282.9 ns
NSubstitute	10	11,201.6 ns
Imposter	10	1,896.7 ns
Moq	100	6,804,897.3 ns
NSubstitute	100	335,390.6 ns
Imposter	100	34,011.7 ns
Moq	1000	99,710,929.5 ns
NSubstitute	1000	26,986,939.0 ns
Imposter	1000	2,452,970.7 ns

Allocated Memory

Method	Iteration	Allocated
Moq	1	13.05 KB
NSubstitute	1	7.84 KB
Imposter	1	2.4 KB
Moq	10	115.73 KB
NSubstitute	10	29.29 KB
Imposter	10	22.37 KB
Moq	100	1416.91 KB
NSubstitute	100	247.26 KB
Imposter	100	222.05 KB
Moq	1000	42275.19 KB
NSubstitute	1000	2420.82 KB
Imposter	1000	2218.93 KB

Benchmark Environment

BenchmarkDotNet v0.15.6, Windows 11 (10.0.26200.6899)
13th Gen Intel Core i9-13900HX 2.20GHz, 1 CPU, 32 logical and 24 physical cores
.NET SDK 10.0.100
[Host]     : .NET 8.0.21 (8.0.21, 8.0.2125.47513), X64 RyuJIT x86-64-v3
DefaultJob : .NET 8.0.21 (8.0.21, 8.0.2125.47513), X64 RyuJIT x86-64-v3

See other benchmarks benchmark

Docs

Docs: https://themidnightgospel.github.io/Imposter/

License

Licensed under the MIT License. See LICENSE.txt for details.

Product	Compatible and additional computed target framework versions.
.NET	net5.0 was computed. net5.0-windows was computed. net6.0 was computed. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 was computed. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 was computed. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. net9.0 was computed. net9.0-android was computed. net9.0-browser was computed. net9.0-ios was computed. net9.0-maccatalyst was computed. net9.0-macos was computed. net9.0-tvos was computed. net9.0-windows was computed. net10.0 was computed. net10.0-android was computed. net10.0-browser was computed. net10.0-ios was computed. net10.0-maccatalyst was computed. net10.0-macos was computed. net10.0-tvos was computed. net10.0-windows was computed.
.NET Core	netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed.
.NET Standard	netstandard2.0 is compatible. netstandard2.1 was computed.
.NET Framework	net461 was computed. net462 was computed. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed.
MonoAndroid	monoandroid was computed.
MonoMac	monomac was computed.
MonoTouch	monotouch was computed.
Tizen	tizen40 was computed. tizen60 was computed.
Xamarin.iOS	xamarinios was computed.
Xamarin.Mac	xamarinmac was computed.
Xamarin.TVOS	xamarintvos was computed.
Xamarin.WatchOS	xamarinwatchos was computed.

Compatible target framework(s)

Included target framework(s) (in package)

Learn more about Target Frameworks and .NET Standard.

.NETStandard 2.0
- No dependencies.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version	Downloads	Last Updated
0.1.4	451	11/24/2025
0.1.3	233	11/24/2025
0.1.2	243	11/22/2025
0.1.1	220	11/22/2025
0.1.0	396	11/17/2025
0.0.24	343	11/17/2025
0.0.23	169	11/15/2025
0.0.22	175	11/15/2025
0.0.21	181	11/15/2025
0.0.20	181	11/15/2025
0.0.19	180	11/15/2025
0.0.18	187	11/15/2025
0.0.13	223	11/14/2025

Fix ignored “putinsamenamespace” flag for targets in global namespace