Mocking two different results from the same method

I have two action methods, edit and delete(both post). These methods invoke methods from a DB interface. These interface method are implemented in a class called DBManager. In these methods a user gets edited and a boolean results is returned, same goes for the delete method, the returned result will either be true or false, depending on whether the deletion or edit was a success or not.

Now I want to mock the two results(true and false), here is my code where I setup the mocks:

//setup passed test
_moqDB.Setup(md => md.EditStaff(It.IsAny<StaffEditViewModel>())).Returns(true);

//setup failed test
_moqDB.Setup(md => md.EditStaff(It.IsAny<StaffEditViewModel>())).Returns(false);

//Setup Delete method test
_moqDB.Setup(x => x.DeleteStaffMember(It.IsAny<int>())).Returns(true);

//delete failed
_moqDB.Setup(x => x.DeleteStaffMember(It.IsAny<int>())).Returns(false);`

Here is my testing code

 [TestMethod]
    public void PostUpdatedUserTest()
    {
        var staffEdit = new StaffEditViewModel()
        {
            BranchID = "HQ",
            SiteID = "TestingSite",
            StaffEmail = "Zandile.Mashele@avisbudget.co.za",
            StaffID = 887,
            StaffNameF = "TestUser",
            StaffNameS = "TestSurname",
            StaffPassword = "****",
            StaffSecurity = UserRoles.Administrator
        };

        //Act
        var result = _userController.Edit(staffEdit);

        //Assert
        Assert.IsNotNull(result);
        Assert.IsInstanceOfType(result, typeof(RedirectToRouteResult));
        var redirectResult = result as RedirectToRouteResult;
        Assert.AreEqual("Index", redirectResult.RouteValues["action"]);
    }

    [TestMethod]
    public void PostUpdatedUserFailTest()
    {
        var staffEdit = new StaffEditViewModel()
        {
            BranchID = "HQ",
            SiteID = "TestSite",
            StaffEmail = "Zandile.Mashele@avisbudget.co.za",
            StaffID = 1,
            StaffNameF = "Test1",
            StaffNameS = "TestSurname",
            StaffPassword = "****",
            StaffSecurity = UserRoles.Administrator
        };

        //Act
        var result = _userController.Edit(staffEdit) as ViewResult;

        // Assert
        Assert.IsNotNull(result);
        Assert.IsTrue(string.IsNullOrEmpty(result.ViewName) || result.ViewName == "Error");
    }

The tests seems to pass only when I run them individually(run one while the other is commented out). My question is, is there a way of running this tests all at once and have them pass, remember I am trying to tests two different scenarios(true and false). They say assumption is the devil of all bugs, now I cannot assume just because false result seems to work fine then also the true result will be perfect