Smocks is a library for mocking the normally unmockable. It can mock static and non-virtual methods and properties, amongst others.
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Smocks is an experimental framework for "static mocking" for .NET 4 and .NET 4.5. It is not a full-featured mocking framework, but rather a supplement to existing frameworks such as moq. These frameworks typically do not support mocking of static or non-virtual methods and properties. Smocks fills the gap.

As an example, you might want to unit test some code that uses the static property DateTime.Now to test if the code performs as expected at January 1st of the next year. Since DateTime.Now is static, it cannot be mocked by most conventional mocking frameworks. Smocks enables you to change the behaviour of such static properties, as well as other unmockables such as non-virtual methods and static methods.


Smocks uses some magic under the hood to mock the normally unmockable. This magic has its (technical) limitations though. Therefore it's very important that you play by the rules. Most importantly: avoid using variables defined outside the scope of Smocks.Run unless you know what you're doing. These are some valid scenarios:

Static properties

Smock.Run(context =>
    context.Setup(() => DateTime.Now).Returns(new DateTime(2000, 1, 1));

    // Outputs "2000"

Static methods

Smock.Run(context =>
    int fortytwo = 42;
    context.Setup(() => int.TryParse("forty-two", out fortytwo)).Returns(true);

    int outResult;
    bool result = int.TryParse("forty-two", out outResult);

    // Outputs "True, 42"
    Console.WriteLine("{0}, {1}", result, outResult);

Non-virtual methods

Smock.Run(context =>
    context.Setup(() => It.IsAny<string>().Equals("Bar")).Returns(true);

    // Outputs "True"

Non-virtual properties

Smock.Run(context =>
    context.Setup(() => It.IsAny<string>().Length).Returns(42);

    // Outputs "42"


Smock.Run(context =>
    Console.CancelKeyPress += (sender, args) => Console.WriteLine("CancelKeyPress handled");
    // Outputs "CancelKeyPress handled"
    context.Raise(() => Console.CancelKeyPress += null, () => Console.CancelKeyPress -= null, default(EventArgs));


Available on NuGet:

PM> Install-Package Smocks


  • Strategies for deciding which assemblies to rewrite
  • .Returns((arg1, arg2) => ...)
  • .Callback((arg1, arg2) => ...)
  • Matching It.Is<T>(x => ...)
  • Support for mocking events
  • Strong-named assemblies
  • .SetupSet(() => ...)


This library is currently in alpha status. I expect plenty of bugs to still be present. Should you encounter any oddities, please submit an issue or pull request. Any feedback will be greatly appreciated.


  • mono.cecil (MIT license): the mindblowing CIL reading/writing library that powers Smocks.
  • moq: the awesome mocking framework that heavily inspired the syntax and functionality of Smocks.
  • AppDomainToolkit: a great source of knowledge on the intricacies of AppDomain.