}

    /**
     * Test method for {@link NtlmHttpServletRequest#getUserPrincipal()}.
     * Verifies that the method returns the correct principal object.
     */
    @Test
    void testGetUserPrincipal() {
        // Act: Call the method under test
        Principal actualPrincipal = ntlmRequest.getUserPrincipal();

        super(req);
        this.principal = principal;
    }

    @Override
    public String getRemoteUser() {
        return this.principal.getName();
    }

    @Override
    public Principal getUserPrincipal() {
        return this.principal;
    }

    @Override
    public String getAuthType() {
        return "NTLM";
    }

        NtlmHttpServletRequest request = new NtlmHttpServletRequest(mockRequest, mockPrincipal);
        assertEquals("user1", request.getRemoteUser());
        assertSame(mockPrincipal, request.getUserPrincipal());
        assertEquals("NTLM", request.getAuthType());
        verify(mockPrincipal, times(1)).getName();
    }

    @ParameterizedTest
    @ValueSource(strings = { "", "   ", "unknown" })

        super(req);
        this.principal = principal;
    }

    @Override
    public String getRemoteUser() {
        return principal.getName();
    }

    @Override
    public Principal getUserPrincipal() {
        return principal;
    }

    @Override
    public String getAuthType() {
        return "NTLM";
    }