Add Metadata Content Type Test

Issue gh-15147

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/web/Saml2MetadataFilterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,8 @@
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.security.saml2.core.TestSaml2X509Credentials;
 import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResolver;
+import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResponse;
+import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResponseResolver;
 import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
 import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistrationRepository;
 import org.springframework.security.saml2.provider.service.registration.TestRelyingPartyRegistrations;
@@ -111,6 +113,19 @@ public void doFilterWhenRelyingPartyRegistrationFoundThenInvokesMetadataResolver
 		verify(this.resolver).resolve(validRegistration);
 	}
 
+	@Test
+	public void doFilterWhenMatchesThenRespondsWithMetadata() throws Exception {
+		Saml2MetadataResponse metadata = new Saml2MetadataResponse("<xml/>", "metadata.xml");
+		Saml2MetadataResponseResolver resolver = mock(Saml2MetadataResponseResolver.class);
+		given(resolver.resolve(this.request)).willReturn(metadata);
+		Saml2MetadataFilter filter = new Saml2MetadataFilter(resolver);
+		filter.doFilter(this.request, this.response, this.chain);
+		assertThat(this.response.getContentType()).isEqualTo("application/samlmetadata+xml;charset=UTF-8");
+		assertThat(this.response.getContentAsString()).isEqualTo("<xml/>");
+		assertThat(this.response.getHeaderValue(HttpHeaders.CONTENT_DISPOSITION)).asString()
+			.isEqualTo("attachment; filename=\"metadata.xml\"; filename*=UTF-8''metadata.xml");
+	}
+
 	@Test
 	public void doFilterWhenCustomRequestMatcherThenUses() throws Exception {
 		this.request.setPathInfo("/path");