/// <summary>
 /// Displays all students test results for one chosen test in the StudentResultView
 /// </summary>
 /// <param name="testId"></param>
 public void DisplayStudentResult(int testId)
 {
     DisplayResult.Clear();
     foreach (TestResult tr in StudentTestResults.ToList())
     {
         foreach (Student student in AllStudents)
         {
             if (tr.TestId == testId && student.StudentId == tr.StudentId)
             {
                 DisplayResult.Add($"TestId: {tr.TestId}\nNamn: {student.FirstName} {student.LastName}\nPoäng: {tr.TotalPoints}");
             }
         }
     }
 }
 /// <summary>
 /// Displays all the tests that have been finished
 /// </summary>
 public void DisplayAllTests()
 {
     GradedTests.Clear();
     foreach (TestResult tr in StudentTestResults.ToList())
     {
         foreach (Test t in AllTests.ToList())
         {
             if (t.TestId == tr.TestId && !GradedTests.Contains(t))
             {
                 GradedTests.Add(t);
             }
         }
     }
 }