CombinatorialStrategy CombinatorialStrategy creates test cases by using all possible combinations of the parameter data.

 DatapointProvider Provides data from fields marked with the DatapointAttribute or the DatapointsAttribute.

 DefaultSuiteBuilder Built-in SuiteBuilder for all types of test classes.

 DefaultTestCaseBuilder Class to build ether a parameterized or a normal NUnitTestMethod. There are four cases that the builder must deal with: 1. The method needs no params and none are provided 2. The method needs params and they are provided 3. The method needs no params but they are provided in error 4. The method needs params but they are not provided This could have been done using two different builders, but it turned out to be simpler to have just one. The BuildFrom method takes a different branch depending on whether any parameters are provided, but all four cases are dealt with in lower-level methods

 NamespaceTreeBuilder Class that can build a tree of automatic namespace suites from a group of fixtures.

 NUnitTestCaseBuilder NUnitTestCaseBuilder is a utility class used by attributes that build test cases.

 NUnitTestFixtureBuilder NUnitTestFixtureBuilder is able to build a fixture given a class marked with a TestFixtureAttribute or an unmarked class containing test methods. In the first case, it is called by the attribute and in the second directly by NUnitSuiteBuilder.

 PairwiseStrategy PairwiseStrategy creates test cases by combining the parameter data so that all possible pairs of data items are used.

 ParameterDataProvider ParameterDataProvider supplies individual argument _values for single parameters using attributes derived from DataAttribute.

 SequentialStrategy SequentialStrategy creates test cases by using all of the parameter data sources in parallel, substituting null when any of them run out of data.