How Would I Make This Test Data Driven?

I have several tests where the only thing which is different from them is the username and I would like to do TestCase[] with them but nothing seems to be working. Here is the test:

    [Test]
    public void SACCanSelectPayments()
    {
        LufasWebManager.OktaDevTenantSignIn(Users.lufas_sac1.ToString(), LufasWebManager.EncryptPassword(_site.GetAuditPassword(Users.lufas_sac1)));
        new MenuBarSubPage(LufasWebManager.Driver).SelectPracticeAudit(MenuBarSubPage.PracticeAuditOptions.WardOrBranch);
        LufasWebManager.Stall(2500);
        LufasWebManager.Driver.FindElement(By.XPath("//simple-snack-bar/div/button")).Click();
        var auditPage = new BaseAudit(LufasWebManager.Driver);
        auditPage.ClickContinue();
        auditPage.ClickContinue();
        var paymentsPage = new AuditAddPaymentsDepositsSubpage(LufasWebManager.Driver);
        SelectPayments(paymentsPage);
    }

The thing which needs to change is in the first line the Users.lufas_sac1. I have tried doing:

[TestCase("lufas_sac1")]
[Test]
public void SACCanSelectPayments(string user)
{
   LufasWebManager.OktaDevTenantSignIn(Users.user.ToString(), LufasWebManager.EncryptPassword(_site.GetAuditPassword(Users.user)));
   ...
}

That didn't work so I tried string interpolation and that didn't work either. I am just not sure how to go about making test cases with the various users so I am not duplicating tests. Got to keep it DRY.

Your example, at least as posted, doesn't use the parameter you are passing.

The name of the parameter is 'user'. It is passed to the method as a string. Your TestCase attribute, gives it the value "lufas_sac1", which I assume is the name of the user you want to use for the test.

OTOH, your code is passing in the name held in Users.user, converting it to a string. NUnit, of course, knows nothing abut your class Users and does nothing to initialize it.

If you change the first argument to the login call to simply 'user' then you will make use of the passed-in argument. However, I suspect you will need to make changes to the second login argument as well. Not enough info here about the Users class to suggest further changes.

BTW, as a matter of style, I'd drop the Test attribute when using TestCase.

Here is my working code, I cast my variable user as type Users and got it working.

    [TestCase(Users.lufas_sac1)]
    [Test]
    public void UserCanSelectPayment(Users user)
    
    {
        LufasWebManager.OktaDevTenantSignIn(user.ToString(), LufasWebManager.EncryptPassword(_site.GetAuditPassword(user)));
        new MenuBarSubPage(LufasWebManager.Driver).SelectPracticeAudit(MenuBarSubPage.PracticeAuditOptions.WardOrBranch);
        LufasWebManager.Stall(2500);
        LufasWebManager.Driver.FindElement(By.XPath("//simple-snack-bar/div/button")).Click();
        var auditPage = new BaseAudit(LufasWebManager.Driver);
        auditPage.ClickContinue();
        auditPage.ClickContinue();
        var paymentsPage = new AuditAddPaymentsDepositsSubpage(LufasWebManager.Driver);
        SelectPayments(paymentsPage);
    }