public async Task CreateNew_InsertOneSubject_ReturnSubjectId()
        {
            //Arrange
            TeacherService     teacherService = new TeacherService(context, context);
            TeacherCreateModel model          = new TeacherCreateModel()
            {
                FirstName = "Dragos",
                LastName  = "Gavrilut",
                Email     = "*****@*****.**",
                Password  = "******"
            };
            var teacherId = await teacherService.CreateNew(model);

            SubjectCreateModel subject = new SubjectCreateModel()
            {
                Name = "C++"
            };

            //Act
            var result = await subjectService.CreateNew(teacherId, subject);

            //Assert
            Assert.IsInstanceOfType(result, typeof(System.Guid));
        }