Add InMemoryRelyingPartyRegistrationTests

Issue gh-12848

Author: jzheaux

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/registration/InMemoryRelyingPartyRegistrationRepositoryTests.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2002-2023 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.registration;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link InMemoryRelyingPartyRegistrationRepository}
+ */
+public class InMemoryRelyingPartyRegistrationRepositoryTests {
+
+	@Test
+	void findByRegistrationIdWhenGivenIdThenReturnsMatchingRegistration() {
+		RelyingPartyRegistration registration = TestRelyingPartyRegistrations.relyingPartyRegistration().build();
+		InMemoryRelyingPartyRegistrationRepository registrations = new InMemoryRelyingPartyRegistrationRepository(
+				registration);
+		assertThat(registrations.findByRegistrationId(registration.getRegistrationId())).isSameAs(registration);
+	}
+
+	@Test
+	void findByRegistrationIdWhenGivenWrongIdThenReturnsNull() {
+		RelyingPartyRegistration registration = TestRelyingPartyRegistrations.relyingPartyRegistration().build();
+		InMemoryRelyingPartyRegistrationRepository registrations = new InMemoryRelyingPartyRegistrationRepository(
+				registration);
+		assertThat(registrations.findByRegistrationId(registration.getRegistrationId() + "wrong")).isNull();
+		assertThat(registrations.findByRegistrationId(null)).isNull();
+	}
+
+}