SpringBoot：使用spring-boot-test对web应用做单元测试时如何测试Filter?

对SpringBoot的Web应用做单元测试时，一般会使用spring-boot-test，pom.xml中会添加如下内容：

		<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>

代码举例如下：

import static org.junit.jupiter.api.Assertions.assertEquals;import javax.annotation.Resource;import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import org.springframework.test.web.servlet.setup.DefaultMockMvcBuilder;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;import com.test.protobuf.App;@RunWith(SpringRunner.class)
@SpringBootTest(classes = App.class)
public class WebAppTester {@Resourceprivate WebApplicationContext ctx = null;private MockMvc mockMvc = null;@Beforepublic void setupMockMvc() throws Exception {DefaultMockMvcBuilder builder = MockMvcBuilders.webAppContextSetup(ctx);this.mockMvc = builder.build();}@Testpublic void test01() throws Exception {String result = doHttpAsyncTest(mockMvc, "/admin/health", "", null);assertEquals("ok", result);}public String doHttpAsyncTest(MockMvc mockMvc, String uri, String httpBody, HttpHeaders httpHeaders)throws Exception {MockHttpServletRequestBuilder builder = MockMvcRequestBuilders.post(uri).contentType(MediaType.APPLICATION_JSON);if (httpHeaders != null) {builder.headers(httpHeaders);}MvcResult result = mockMvc.perform(builder.content(httpBody)).andReturn();String httpRespBody = mockMvc.perform(MockMvcRequestBuilders.asyncDispatch(result)).andExpect(MockMvcResultMatchers.status().isOk()).andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON)).andReturn().getResponse().getContentAsString();return httpRespBody;}}

如果应用中以如下方式添加了Filter的话，使用以上代码无法测试这些Filter：

import java.io.IOException;import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class TestFilter implements Filter {private String checkUrl = "/";@Overridepublic void init(FilterConfig config) throws ServletException {String checkUrl = config.getInitParameter("checkUrl");if (checkUrl != null) {this.checkUrl = checkUrl;}}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {HttpServletRequest httpReqt = (HttpServletRequest) request;String reqtUrl = httpReqt.getRequestURI();if (!reqtUrl.startsWith(checkUrl)) {chain.doFilter(request, response);return;}HttpServletResponse httpResp = (HttpServletResponse) response;httpResp.setStatus(200);httpResp.setContentType("text/plain");httpResp.getWriter().write("ok");return;}}

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Configuration;@Configuration
public class FilterRegistrationConfig {public FilterRegistrationBean<TestFilter> testFilter() {FilterRegistrationBean<TestFilter> reg = new FilterRegistrationBean<TestFilter>();reg.setFilter(new TestFilter());reg.addInitParameter("checkUrl", "/admin/");reg.setName("TestFilter");return reg;}
}

如果想把这些Filter也测试到，需要在setupMockMvc方法中将Filter注册并初始化一下，代码如下：

import com.test.protobuf.App;@RunWith(SpringRunner.class)
@SpringBootTest(classes = App.class)
public class WebAppTester {@Resourceprivate WebApplicationContext ctx = null;private MockMvc mockMvc = null;@Resourceprivate FilterRegistrationBean<?>[] filterRegistrationBean = null;@Beforepublic void setupMockMvc() throws Exception {DefaultMockMvcBuilder builder = MockMvcBuilders.webAppContextSetup(ctx);for (FilterRegistrationBean<?> bean : filterRegistrationBean) {MockFilterConfig filterConfig = new MockFilterConfig();for (Entry<String, String> params : bean.getInitParameters().entrySet()) {filterConfig.addInitParameter(params.getKey(), params.getValue());}Filter filter = bean.getFilter();filter.init(filterConfig);builder.addFilter(filter, bean.getUrlPatterns().toArray(new String[0]));}this.mockMvc = builder.build();}
......
}