AssertionResult The AssertionResult class represents the result of a single assertion.

 ResultState The ResultState class represents the outcome of running a test. It contains two pieces of information. The Status of the test is an enum indicating whether the test passed, failed, was skipped or was inconclusive. The Label provides a more detailed breakdown for use by client runners.

 TestAttachment The TestAttachment class represents a file attached to a TestResult, with an optional description.

 TestMessage The class holds a message sent by a test to all listeners

 TestOutput The TestOutput class holds a unit of output from a test to a specific output stream

 TNode TNode represents a single node in the XML representation of a Test or TestResult. It replaces System.Xml.XmlNode and System.Xml.Linq.XElement, providing a minimal set of methods for operating on the XML in a platform-independent manner.

 AssertionStatus AssertionStatus enumeration represents the possible outcomes of an assertion. The order of definition is significant, higher level values override lower ones in determining the overall result of a test.

 FailureSite The FailureSite enum indicates the stage of a test in which an error or failure occurred.

 RunState The RunState enum indicates whether a test can be executed.

 TestStatus The TestStatus enum indicates the result of running a test

 IApplyToContext The IApplyToContext interface is implemented by attributes that want to make changes to the execution context before a test is run.

 IApplyToTest The IApplyToTest interface is implemented by self-applying attributes that modify the state of a test in some way.

 IApplyToTestSuite The IApplyToTestSuite interface is implemented by self-applying attributes that modify the state of a test suite in some way.

 ICombiningStrategy CombiningStrategy is the abstract base for classes that know how to combine values provided for individual test parameters to create a set of test cases.

 ICommandWrapper ICommandWrapper is implemented by attributes and other objects able to wrap a TestCommand with another command.

 IFixtureBuilder The IFixtureBuilder interface is exposed by a class that knows how to build test fixtures from a specified type. In general, it is exposed by an attribute, but it may be implemented in a helper class used by the attribute in some cases.

 IFixtureBuilder2 The IFixtureBuilder2 interface extends IFixtureBuilder by allowing use of a PreFilter, which is used to select methods as test cases.

 IImplyFixture IImplyFixture is an empty marker interface used by attributes like TestAttribute that cause the class where they are used to be treated as a TestFixture even without a TestFixtureAttribute. Marker interfaces are not usually considered a good practice, but we use it here to avoid cluttering the attribute hierarchy with classes that don't contain any extra implementation.

 IMethodInfo The IMethodInfo class is used to encapsulate information about a method in a platform-independent manner.

 IParameterDataProvider Provides data for a single test parameter.

 IParameterDataSource Provides data for a single test parameter.

 IParameterInfo The IParameterInfo interface is an abstraction of a .NET parameter.

 IPreFilter Implemented by filters for use in deciding which Types and Methods should be used to generate tests.

 IPropertyBag A PropertyBag represents a collection of name/value pairs that allows duplicate entries with the same key. Methods are provided for adding a new pair as well as for setting a key to a single value. All keys are strings but values may be of any type. Null values are not permitted, since a null entry represents the absence of the key. The entries in a PropertyBag are of two kinds: those that take a single value and those that take multiple values. However, the PropertyBag has no knowledge of which entries fall into each category and the distinction is entirely up to the code using the PropertyBag. When working with multi-valued properties, client code should use the Add method to add name/value pairs and indexing to retrieve a list of all values for a given key. For example: bag.Add("Tag", "one"); bag.Add("Tag", "two"); Assert.That(bag["Tag"], Is.EqualTo(new string[] { "one", "two" })); When working with single-valued properties, client code should use the Set method to set the value and Get to retrieve the value. The GetSetting methods may also be used to retrieve the value in a type-safe manner while also providing default. For example: bag.Set("Priority", "low"); bag.Set("Priority", "high"); // replaces value Assert.That(bag.Get("Priority"), Is.EqualTo("high")); Assert.That(bag.GetSetting("Priority", "low"), Is.EqualTo("high"));

 IReflectionInfo The IReflectionInfo interface is implemented by NUnit wrapper objects that perform reflection.

 IRepeatTest Objects implementing this interface are used to wrap tests that can repeat. The implementing command is run once, invoking the chained commands any number of times.

 ISimpleTestBuilder The ISimpleTestBuilder interface is exposed by a class that knows how to build a single tests from a specified method. In general, it is exposed by an attribute, but it may be implemented in a helper class used by the attribute in some cases.

 ISuiteBuilder The ISuiteBuilder interface is exposed by a class that knows how to build a single test suite from a specified type.

 ITest Common interface supported by all representations of a test. Only includes informational fields. The Run method is specifically excluded to allow for data-only representations of a test.

 ITestBuilder The ITestBuilder interface is exposed by a class that knows how to build tests from a specified method. In general, it is exposed by an attribute which has additional information available to provide the necessary test parameters to distinguish the test cases built.

 ITestCaseBuilder The ITestCaseBuilder interface is exposed by a class that knows how to build a test from a specified method, possibly containing child test cases.

 ITestCaseData The ITestCaseData interface is implemented by a class that is able to return complete test cases for use by a parameterized test method.

 ITestData The ITestData interface is implemented by a class that represents a single instance of a parameterized test.

 ITestFilter Interface to be implemented by filters applied to tests. The filter applies when running the test, after it has been loaded, since this is the only time an ITest exists.

 ITestFixtureData The ITestCaseData interface is implemented by a class that is able to return the data required to create an instance of a parameterized test fixture.

 ITestListener The ITestListener interface is used internally to receive notifications of significant events while a test is being run. The events are propagated to clients by means of an AsyncCallback. NUnit extensions may also monitor these events.

 ITestResult The ITestResult interface represents the result of a test.

 ITypeInfo The ITypeInfo interface is an abstraction of a .NET Type

 IWrapSetUpTearDown Objects implementing this interface are used to wrap the entire test, including SetUp and TearDown.

 IWrapTestMethod Objects implementing this interface are used to wrap the TestMethodCommand itself. They apply after SetUp has been run and before TearDown.

 IXmlNodeBuilder An object implementing IXmlNodeBuilder is able to build an XML representation of itself and any children.