How to test if a SharePoint connect is successful with user credentials using Unit testing C#

I am working on a project where I am trying to test if a user has successfully logged in with valid credentials using the Microsoft.SharePoint.Client.dll.

Currently my code is checking the HTTP Response code for the SharePoint URL - however it is not checking to see if the user has passed in valid credentials.

For example - I can change my password, and the test will still pass since the code is only seeing if it is being passed a valid endpoint.

Is there a way with the Microsoft.SharePoint.Client.dll to see if a user has provided proper credentials?

Current Test

    [TestMethod]
    public void ConnectionToSharePoint_IsSuccessful()
    {
        var sharePointConnection = _sharePointService.OpenConnectionToSharePoint();
        var webRequest = (HttpWebRequest) WebRequest
            .Create(sharePointConnection.Url);
        var responce = (HttpWebResponse) webRequest.GetResponse();

        Assert.AreEqual(HttpStatusCode.OK,responce.StatusCode);
    }