OneTimeSetUp Attribute

jnm2 edited this page Jun 14, 2017 · 5 revisions

This attribute is to identify methods that are called once prior to executing any of the tests in a fixture. It may appear on methods of a TestFixture or a SetUpFixture.

OneTimeSetUp methods may be either static or instance methods and you may define more than one of them in a fixture. Normally, multiple OneTimeSetUp methods are only defined at different levels of an inheritance hierarchy, as explained below.

If a OneTimeSetUp method fails or throws an exception, none of the tests in the fixture are executed and a failure or error is reported.


namespace NUnit.Tests
  using System;
  using NUnit.Framework;

  public class SuccessTests
    public void Init()
    { /* ... */ }

    public void Cleanup()
    { /* ... */ }

    public void Add()
    { /* ... */ }


The OneTimeSetUp attribute is inherited from any base class. Therefore, if a base class has defined a OneTimeSetUp method, that method will be called before any methods in the derived class.

You may define a OneTimeSetUp method in the base class and another in the derived class. NUnit will call base class OneTimeSetUp methods before those in the derived classes.


  1. Although it is possible to define multiple OneTimeSetUp methods in the same class, you should rarely do so. Unlike methods defined in separate classes in the inheritance hierarchy, the order in which they are executed is not guaranteed.

  2. OneTimeSetUp methods may be async if running under .NET 4.0 or higher.

See also...

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