public void GetOutputMultipleGroup() { // Arrange var input = new List <Student> { new Student() { GroupId = 1, Name = "Paul", TimeIndex = 0, MarkIndex = 1 }, new Student() { GroupId = 1, Name = "Fred", TimeIndex = 1, MarkIndex = 0 }, new Student() { GroupId = 2, Name = "John", TimeIndex = 2, MarkIndex = 2 } }; var expected = new String[, ] { { "Paul", "Fred" }, { "John", "" } }; // Act var logger = new Logger(); var studentCore = new StudentCore(logger); var actual = studentCore.GetOutput(input); // Assert CollectionAssert.AreEqual(expected, actual); }