Make the loginProcessingUrl configurable for saml2Login()

Fixes gh-7565

https://github.com/spring-projects/spring-security/issues/7565

samples/boot/saml2login/src/integration-test/java/org/springframework/security/samples/Saml2LoginIntegrationTests.java

@@ -51,7 +51,6 @@ import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.context.annotation.ComponentScan;
 import org.springframework.http.MediaType;
 import org.springframework.security.saml2.provider.service.authentication.Saml2AuthenticationException;
 import org.springframework.test.context.junit4.SpringRunner;
@@ -111,7 +110,6 @@ public class Saml2LoginIntegrationTests {
 
 	@SpringBootConfiguration
 	@EnableAutoConfiguration
-	@ComponentScan(basePackages = "sample")
 	public static class SpringBootApplicationTestConfig {
 
 	}

samples/javaconfig/saml2login/src/main/java/org/springframework/security/samples/config/SecurityConfig.java

@@ -76,6 +76,7 @@ public class SecurityConfig extends WebSecurityConfigurerAdapter {
 							getSaml2AuthenticationConfiguration()
 					)
 				)
+				.loginProcessingUrl("/sample/jc/saml2/sso/{registrationId}")
 		;
 		// @formatter:on
 	}

samples/javaconfig/saml2login/src/test/java/org/springframework/security/samples/config/SecurityConfigTests.java

@@ -15,17 +15,46 @@
  */
 package org.springframework.security.samples.config;
 
-import org.springframework.test.context.ContextConfiguration;
-import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
-
+import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.security.saml2.provider.service.servlet.filter.Saml2WebSsoAuthenticationFilter;
+import org.springframework.security.web.FilterChainProxy;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.util.ReflectionTestUtils;
+
+import java.util.List;
+import javax.servlet.Filter;
 
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration(classes = SecurityConfig.class)
 public class SecurityConfigTests {
 
+	@Autowired
+	ApplicationContext context;
+
 	@Test
 	public void securityConfigurationLoads() {
 	}
+
+	@Test
+	public void filterWhenLoginProcessingUrlIsSetInJavaConfigThenTheFilterHasIt() {
+		FilterChainProxy filterChain = context.getBean(FilterChainProxy.class);
+		Assert.assertNotNull(filterChain);
+		final List<Filter> filters = filterChain.getFilters("/sample/jc/saml2/sso/test-id");
+		Assert.assertNotNull(filters);
+		Saml2WebSsoAuthenticationFilter filter = (Saml2WebSsoAuthenticationFilter) filters
+				.stream()
+				.filter(
+						f -> f instanceof Saml2WebSsoAuthenticationFilter
+				)
+				.findFirst()
+				.get();
+		final Object matcher = ReflectionTestUtils.getField(filter, "requiresAuthenticationRequestMatcher");
+		final Object pattern = ReflectionTestUtils.getField(matcher, "pattern");
+		Assert.assertEquals("loginProcessingUrl mismatch", "/sample/jc/saml2/sso/{registrationId}", pattern);
+	}
 }