Tes unit HandleAuthenticateAsync

        [TestMethod]
        public async Task HandleAuthenticateAsync_CredentialsTryParseFails_ReturnsAuthenticateResultFail()
        {
            var context = new DefaultHttpContext();
            var authorizationHeader = new StringValues(String.Empty);
            context.Request.Headers.Add(HeaderNames.Authorization, authorizationHeader);

            await _handler.InitializeAsync(new AuthenticationScheme(BasicAuthenticationHandler.SchemeName, null, typeof(BasicAuthenticationHandler)), context);
            var result = await _handler.AuthenticateAsync();

            Assert.IsFalse(result.Succeeded);
            Assert.AreEqual("Basic authentication failed.  Unable to parse username and password.", result.Failure.Message);
        }

        [TestMethod]
        public async Task HandleAuthenticateAsync_PrincipalIsNull_ReturnsAuthenticateResultFail()
        {
            _principalProvider.Setup(m => m.GetClaimsPrincipalAsync(It.IsAny<String>(), It.IsAny<String>(), It.IsAny<String>())).ReturnsAsync((ClaimsPrincipal)null);

            var context = new DefaultHttpContext();
            var authorizationHeader = new StringValues("Basic VGVzdFVzZXJOYW1lOlRlc3RQYXNzd29yZA==");
            context.Request.Headers.Add(HeaderNames.Authorization, authorizationHeader);

            await _handler.InitializeAsync(new AuthenticationScheme(BasicAuthenticationHandler.SchemeName, null, typeof(BasicAuthenticationHandler)), context);
            var result = await _handler.AuthenticateAsync();

            Assert.IsFalse(result.Succeeded);
            Assert.AreEqual("Basic authentication failed.  Invalid username and password.", result.Failure.Message);
        }

        [TestMethod]
        public async Task HandleAuthenticateAsync_PrincipalIsNull_ReturnsAuthenticateResultSuccessWithPrincipalInTicket()
        {
            var username = "TestUserName";
            var claims = new[] { new Claim(ClaimTypes.Name, username) };
            var identity = new ClaimsIdentity(claims, BasicAuthenticationHandler.SchemeName);
            var claimsPrincipal = new ClaimsPrincipal(identity);
            _principalProvider.Setup(m => m.GetClaimsPrincipalAsync(It.IsAny<String>(), It.IsAny<String>(), It.IsAny<String>())).ReturnsAsync(claimsPrincipal);

            var context = new DefaultHttpContext();
            var authorizationHeader = new StringValues("Basic VGVzdFVzZXJOYW1lOlRlc3RQYXNzd29yZA==");
            context.Request.Headers.Add(HeaderNames.Authorization, authorizationHeader);

            await _handler.InitializeAsync(new AuthenticationScheme(BasicAuthenticationHandler.SchemeName, null, typeof(BasicAuthenticationHandler)), context);
            var result = await _handler.AuthenticateAsync();

            Assert.IsTrue(result.Succeeded);
            Assert.AreEqual(BasicAuthenticationHandler.SchemeName, result.Ticket.AuthenticationScheme);
            Assert.AreEqual(username, result.Ticket.Principal.Identity.Name);
        }
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