public void GetClientFileName_DirectoryINotEmpty_GotLastFileName() { // arrange appSettingsDictionary["winClientFolder"] = "anyValue"; directoryWrapperMock.Setup(x => x.GetFiles("\\anyPath\\anyValue", "SedWinClient*")) .Returns(() => stubFileNames); // act var fileNames = applicationConfigurationManager.GetClientFileName(); // assert Assert.AreEqual("3.txt", fileNames); }