how to mock a method of a class - unit-testing

Question

This is my controller code and I need to mock GetTokenDetails() method to conduct XUnit test on DecodeToken function. Am I doing in right way or not?
[HttpGet]
[Authorize(Roles = "Admin")]
[Route("DecodeToken")]
public IActionResult DecodeToken()
{
if (ModelState.IsValid)
{
var tokenResult = GetTokenDetails();
var result = _employeeService.ServiceDecodeToken(tokenResult.UserName, tokenResult.Role);
if (result.Httpcode == 200)
{
return Ok(result);
}
else
{
return StatusCode(500, result);
}
}
else
return BadRequest();
}
public GetTokenDetailsDto GetTokenDetails()
{
var token = HttpContext.Request.Headers["Authorization"].ToString();
var tokenbearer = token.Split(' ');
var handler = new JwtSecurityTokenHandler();
var decodedtoken = handler.ReadJwtToken(tokenbearer[1]);
string user = decodedtoken.Claims.Where(x => x.Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name").FirstOrDefault().ToString();
string role = decodedtoken.Claims.Where(x => x.Type == "http://schemas.microsoft.com/ws/2008/06/identity/claims/role").FirstOrDefault().ToString();
var usr = user.Split(":");
var rol = role.Split(":");
string userName = usr[2].Trim();
string userRole = rol[2].Trim();
GetTokenDetailsDto getTokenDetailsDto = new GetTokenDetailsDto()
{
UserName = userName,
Role = userRole,
};
return getTokenDetailsDto;
}

Answer 1

First, Generally, I don't think there is a right way to do something.
There are multiple right ways to do it :). You just need to pick one or create one.
Second, I suggest you to create a new Dotnet standard Project under the same Solution and separate the logic from controllers. This way, you can create a Unit test project and import only the logic project.
Third, I see some points in your code that you are reading some value from the context( which is not avaiable in testing environment). For example, HttpContext.Request.Headers["Authorization"]. these kind of data should be in the input arguments of the function GetTokenDetails, so you can provide some sample data to test in your UnitTestProject. Something like this:
public GetTokenDetailsDto GetTokenDetails(string token)
{
var tokenbearer = token.Split(' ');
var handler = new JwtSecurityTokenHandler();
var decodedtoken = handler.ReadJwtToken(tokenbearer[1]);
string user = decodedtoken.Claims.Where(x => x.Type == "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name").FirstOrDefault().ToString();
string role = decodedtoken.Claims.Where(x => x.Type == "http://schemas.microsoft.com/ws/2008/06/identity/claims/role").FirstOrDefault().ToString();
var usr = user.Split(":");
var rol = role.Split(":");
string userName = usr[2].Trim();
string userRole = rol[2].Trim();
GetTokenDetailsDto getTokenDetailsDto = new GetTokenDetailsDto()
{
UserName = userName,
Role = userRole,
};
return getTokenDetailsDto;
}