src/test/java/com/resumeparser/config/RateLimitInterceptorTest.java

package com.resumeparser.config;

import com.resumeparser.service.FirestoreRateLimiterService;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;

class RateLimitInterceptorTest {

    private FirestoreRateLimiterService rateLimiterService;
    private RateLimitInterceptor interceptor;

    @BeforeEach
    void setUp() {
        rateLimiterService = mock(FirestoreRateLimiterService.class);
        interceptor = new RateLimitInterceptor(rateLimiterService);
    }

    @Test
    void shouldAllowOptionsRequestsWithoutRateLimiting() throws Exception {
        MockHttpServletRequest request = new MockHttpServletRequest();
        request.setMethod("OPTIONS");
        MockHttpServletResponse response = new MockHttpServletResponse();

        boolean result = interceptor.preHandle(request, response, new Object());

        assertTrue(result);
        verifyNoInteractions(rateLimiterService);
    }

    @Test
    void shouldAllowRequestWhenUnderLimit() throws Exception {
        MockHttpServletRequest request = new MockHttpServletRequest();
        request.setMethod("POST");
        request.setRemoteAddr("192.168.1.50");
        MockHttpServletResponse response = new MockHttpServletResponse();

        when(rateLimiterService.isAllowed("192.168.1.50")).thenReturn(true);

        boolean result = interceptor.preHandle(request, response, new Object());

        assertTrue(result);
        assertEquals(200, response.getStatus());
    }

    @Test
    void shouldBlockRequestWith429WhenLimitExceeded() throws Exception {
        MockHttpServletRequest request = new MockHttpServletRequest();
        request.setMethod("POST");
        request.setRemoteAddr("192.168.1.50");
        MockHttpServletResponse response = new MockHttpServletResponse();

        when(rateLimiterService.isAllowed("192.168.1.50")).thenReturn(false);

        boolean result = interceptor.preHandle(request, response, new Object());

        assertFalse(result);
        assertEquals(429, response.getStatus());
        assertTrue(response.getContentAsString().contains("Too many requests"));
    }

    @Test
    void shouldExtractIpFromXForwardedForHeader() throws Exception {
        MockHttpServletRequest request = new MockHttpServletRequest();
        request.setMethod("POST");
        request.addHeader("X-Forwarded-For", "203.0.113.195, 10.0.0.1");
        request.setRemoteAddr("127.0.0.1");
        MockHttpServletResponse response = new MockHttpServletResponse();

        when(rateLimiterService.isAllowed("203.0.113.195")).thenReturn(true);

        boolean result = interceptor.preHandle(request, response, new Object());

        assertTrue(result);
        verify(rateLimiterService).isAllowed("203.0.113.195");
    }
}