我知道如何从 C# 代码运行完整的 NUnit 程序集
TestPackage testPackage = new TestPackage(assemblyName);
RemoteTestRunner remoteTestRunner = new RemoteTestRunner();
remoteTestRunner.Load(testPackage);
TestResult testResult = remoteTestRunner.Run(new NullListener(), TestFilter.Empty, false, LoggingThreshold.Error);
但是我怎样才能运行单个 TestFixtures 甚至单个测试呢?