Revert "Remove CAS module"

This reverts commit caf4c471

config/src/test/java/org/springframework/security/config/annotation/web/builders/HttpConfigurationTests.java

@@ -20,6 +20,8 @@ import java.io.IOException;
 
 import jakarta.servlet.FilterChain;
 import jakarta.servlet.ServletException;
+import jakarta.servlet.ServletRequest;
+import jakarta.servlet.ServletResponse;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import org.junit.jupiter.api.Test;
@@ -29,6 +31,8 @@ import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.security.cas.web.CasAuthenticationFilter;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
 import org.springframework.security.config.test.SpringTestContext;
 import org.springframework.security.config.test.SpringTestContextExtension;
@@ -42,6 +46,9 @@ import org.springframework.web.filter.OncePerRequestFilter;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
 
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
 
@@ -68,6 +75,16 @@ public class HttpConfigurationTests {
 						+ " Consider using addFilterBefore or addFilterAfter instead.");
 	}
 
+	// https://github.com/spring-projects/spring-security-javaconfig/issues/104
+	@Test
+	public void configureWhenAddFilterCasAuthenticationFilterThenFilterAdded() throws Exception {
+		CasAuthenticationFilterConfig.CAS_AUTHENTICATION_FILTER = spy(new CasAuthenticationFilter());
+		this.spring.register(CasAuthenticationFilterConfig.class).autowire();
+		this.mockMvc.perform(get("/"));
+		verify(CasAuthenticationFilterConfig.CAS_AUTHENTICATION_FILTER).doFilter(any(ServletRequest.class),
+				any(ServletResponse.class), any(FilterChain.class));
+	}
+
 	@Test
 	public void configureWhenConfigIsRequestMatchersJavadocThenAuthorizationApplied() throws Exception {
 		this.spring.register(RequestMatcherRegistryConfigs.class).autowire();
@@ -107,6 +124,21 @@ public class HttpConfigurationTests {
 
 	}
 
+	@EnableWebSecurity
+	static class CasAuthenticationFilterConfig extends WebSecurityConfigurerAdapter {
+
+		static CasAuthenticationFilter CAS_AUTHENTICATION_FILTER;
+
+		@Override
+		protected void configure(HttpSecurity http) {
+			// @formatter:off
+			http
+				.addFilter(CAS_AUTHENTICATION_FILTER);
+			// @formatter:on
+		}
+
+	}
+
 	@Configuration
 	@EnableWebSecurity
 	@EnableWebMvc