public void Operations()
 {
     Assert.AreNotEqual(Calcul.Opérations(Calcul.GetInt("20"), Calcul.GetInt("15"), '+'), 0);
     Assert.AreEqual(Calcul.Opérations(Calcul.GetInt("20"), Calcul.GetInt("15"), '+'), 35);
     Assert.AreEqual(Calcul.Opérations(Calcul.GetInt("2"), Calcul.GetInt("5"), '*'), 10);
     Assert.AreEqual(Calcul.Opérations(Calcul.GetInt("20"), Calcul.GetInt("2"), '/'), 10);
     Assert.AreEqual(Calcul.Opérations(Calcul.GetInt("100"), Calcul.GetInt("1000"), '-'), -900);
 }