public void TestStudentCourse()
        {
            var st = new Student("1234", "Anna", "Nova");

            var sc = new StudentCourseEvaluation(st);

            Assert.AreEqual(st, sc.Student);
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());

            var eval = new CourseEvaluation();

            sc = new StudentCourseEvaluation(st, eval);
            Assert.AreEqual(st, sc.Student);
            Assert.AreEqual(eval, sc.Evaluation);
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());

            sc = new StudentCourseEvaluation("1234", "Anna", "Nova");
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());

            sc = new StudentCourseEvaluation("1234", "Anna", "Nova", eval);
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());

            var evalDef = new EvaluationDefinitionCollection();

            sc = new StudentCourseEvaluation(st, evalDef);
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());

            sc = new StudentCourseEvaluation("1234", "Anna", "Nova", evalDef);
            Assert.AreEqual("1234\tNOVA Anna\t?b", sc.ToString());
        }