Add regression test for MessageChatMemoryAdvisor with Prompt message list (GH-2339)

- Adds an integration test to verify that MessageChatMemoryAdvisor works correctly when a Prompt is initialized with a List<Message>.
- References and confirms the fix for [https://github.com/spring-projects/spring-ai/issues/2339.](https://github.com/spring-projects/spring-ai/issues/2339.)

Signed-off-by: Mark Pollack <mark.pollack@broadcom.com>

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/chat/client/OpenAiChatClientMemoryAdvisorReproIT.java

@@ -0,0 +1,53 @@
+package org.springframework.ai.openai.chat.client;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
+
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.ai.chat.client.advisor.MessageChatMemoryAdvisor;
+import org.springframework.ai.chat.memory.ChatMemory;
+import org.springframework.ai.chat.memory.InMemoryChatMemoryRepository;
+import org.springframework.ai.chat.memory.MessageWindowChatMemory;
+import org.springframework.ai.chat.messages.Message;
+import org.springframework.ai.chat.messages.UserMessage;
+import org.springframework.ai.chat.prompt.Prompt;
+import org.springframework.ai.openai.OpenAiTestConfiguration;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ActiveProfiles;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@SpringBootTest(classes = OpenAiTestConfiguration.class)
+@EnabledIfEnvironmentVariable(named = "OPENAI_API_KEY", matches = ".+")
+@ActiveProfiles("logging-test")
+/**
+ * Integration test for https://github.com/spring-projects/spring-ai/issues/2339 Verifies
+ * that MessageChatMemoryAdvisor works when Prompt is initialized with List<Message>.
+ */
+class OpenAiChatClientMemoryAdvisorReproIT {
+
+	@Autowired
+	private org.springframework.ai.chat.model.ChatModel chatModel;
+
+	@Test
+	void messageChatMemoryAdvisor_withPromptMessages_throwsException() {
+		// Arrange: create a Prompt with a List<Message> (including UserMessage)
+		Message userMessage = new UserMessage("Tell me a joke.");
+		List<Message> messages = List.of(userMessage);
+		Prompt prompt = new Prompt(messages);
+		ChatMemory chatMemory = MessageWindowChatMemory.builder()
+			.chatMemoryRepository(new InMemoryChatMemoryRepository())
+			.build();
+		MessageChatMemoryAdvisor advisor = new MessageChatMemoryAdvisor(chatMemory);
+
+		ChatClient chatClient = ChatClient.builder(chatModel).defaultAdvisors(advisor).build();
+
+		// Act: call should succeed without exception (issue #2339 is fixed)
+		chatClient.prompt(prompt).call().chatResponse(); // Should not throw
+
+	}
+
+}