feat(chroma): improve handling and testing of complex metadata values

- Convert non-primitive metadata values to JSON strings in ChromaApi.AddEmbeddingsRequest for compatibility
- Add tests to verify metadata conversion and complex metadata handling in Chroma vector store integration
- Ensure OpenAiChatModel always returns annotations as a list of maps in metadata
- Add test dependency on spring-ai-advisors-vector-store for advisor-related tests
- Add json-unit-assertj for improved JSON assertions and validating JSON content in tests

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

auto-configurations/vector-stores/spring-ai-autoconfigure-vector-store-chroma/pom.xml

@@ -103,5 +103,12 @@
 			<version>${project.parent.version}</version>
 			<scope>test</scope>
 		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.ai</groupId>
+			<artifactId>spring-ai-advisors-vector-store</artifactId>
+			<version>${project.parent.version}</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 </project>

auto-configurations/vector-stores/spring-ai-autoconfigure-vector-store-chroma/src/test/java/org/springframework/ai/vectorstore/chroma/autoconfigure/ChromaVectorStoreAutoConfigurationIT.java

@@ -28,6 +28,13 @@ import org.testcontainers.chromadb.ChromaDBContainer;
 import org.testcontainers.junit.jupiter.Container;
 import org.testcontainers.junit.jupiter.Testcontainers;
 
+import org.springframework.ai.chat.client.ChatClientRequest;
+import org.springframework.ai.chat.client.ChatClientResponse;
+import org.springframework.ai.chat.client.advisor.vectorstore.VectorStoreChatMemoryAdvisor;
+import org.springframework.ai.chat.messages.AssistantMessage;
+import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.model.Generation;
+import org.springframework.ai.chat.prompt.Prompt;
 import org.springframework.ai.chroma.vectorstore.ChromaVectorStore;
 import org.springframework.ai.document.Document;
 import org.springframework.ai.embedding.EmbeddingModel;
@@ -68,6 +75,39 @@ public class ChromaVectorStoreAutoConfigurationIT {
 				"spring.ai.vectorstore.chroma.client.port=" + chroma.getMappedPort(8000),
 				"spring.ai.vectorstore.chroma.collectionName=TestCollection");
 
+	@Test
+	public void verifyThatChromaCanHandleComplexMetadataValues() {
+		this.contextRunner.withPropertyValues("spring.ai.vectorstore.chroma.initializeSchema=true").run(context -> {
+
+			VectorStore vectorStore = context.getBean(VectorStore.class);
+
+			VectorStoreChatMemoryAdvisor advisor = VectorStoreChatMemoryAdvisor.builder(vectorStore)
+				.defaultTopK(5)
+				.build();
+
+			assertThat(advisor.getName()).isEqualTo("VectorStoreChatMemoryAdvisor");
+
+			var req = ChatClientRequest.builder().prompt(Prompt.builder().content("UserPrompt").build()).build();
+
+			ChatClientRequest req2 = advisor.before(req, null);
+			assertThat(req2).isNotNull();
+
+			var response = ChatClientResponse.builder()
+				.chatResponse(ChatResponse.builder()
+					.generations(List
+						.of(new Generation(new AssistantMessage("AssistantMessage", Map.of("annotations", List.of())))))
+					.build())
+				.build();
+			var res2 = advisor.after(response, null);
+			assertThat(res2).isNotNull();
+
+			// Remove all documents from the store
+			List<Document> docs = vectorStore.similaritySearch("UserPrompt, AssistantMessage");
+			vectorStore.delete(docs.stream().map(doc -> doc.getId()).toList());
+
+		});
+	}
+
 	@Test
 	public void addAndSearchWithFilters() {
 

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatModel.java

@@ -219,7 +219,7 @@ public class OpenAiChatModel implements ChatModel {
 							"index", choice.index(),
 							"finishReason", choice.finishReason() != null ? choice.finishReason().name() : "",
 							"refusal", StringUtils.hasText(choice.message().refusal()) ? choice.message().refusal() : "",
-							"annotations", choice.message().annotations() != null ? choice.message().annotations() : List.of());
+							"annotations", choice.message().annotations() != null ? choice.message().annotations() : List.of(Map.of()));
 					return buildGeneration(choice, metadata, request);
 				}).toList();
 				// @formatter:on

pom.xml

@@ -309,6 +309,7 @@
 
 		<!-- testing dependencies -->
 		<okhttp3.version>4.12.0</okhttp3.version>
+		<json-unit-assertj.version>4.1.0</json-unit-assertj.version>
 
 		<!-- MCP-->
 		<mcp.sdk.version>0.10.0</mcp.sdk.version>

vector-stores/spring-ai-chroma-store/pom.xml

@@ -95,6 +95,14 @@
 			<version>${project.parent.version}</version>
 			<scope>test</scope>
 		</dependency>
+
+		<dependency>
+			<groupId>net.javacrumbs.json-unit</groupId>
+			<artifactId>json-unit-assertj</artifactId>
+			<version>${json-unit-assertj.version}</version>
+			<scope>test</scope>
+		</dependency>
+
 	</dependencies>
 
 </project>

vector-stores/spring-ai-chroma-store/src/main/java/org/springframework/ai/chroma/vectorstore/ChromaApi.java

@@ -30,6 +30,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 
 import org.springframework.ai.chroma.vectorstore.ChromaApi.QueryRequest.Include;
 import org.springframework.ai.chroma.vectorstore.common.ChromaApiConstants;
+import org.springframework.ai.util.json.JsonParser;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.support.BasicAuthenticationInterceptor;
@@ -443,7 +444,27 @@ public class ChromaApi {
 			@JsonProperty("metadatas") List<Map<String, Object>> metadata,
 			@JsonProperty("documents") List<String> documents) { // @formatter:on
 
-		// Convenance for adding a single embedding.
+		public AddEmbeddingsRequest {
+			// Process metadata to ensure all values are Integer, Boolean, or String.
+			// Other types are converted to JSON string using JsonParser.toJson().
+			List<Map<String, Object>> processedMetadatas = new ArrayList<>();
+			for (Map<String, Object> meta : metadata) {
+				Map<String, Object> processed = new HashMap<>();
+				for (Map.Entry<String, Object> entry : meta.entrySet()) {
+					Object value = entry.getValue();
+					if (value instanceof Number || value instanceof Boolean || value instanceof String) {
+						processed.put(entry.getKey(), value);
+					}
+					else {
+						processed.put(entry.getKey(), JsonParser.toJson(value));
+					}
+				}
+				processedMetadatas.add(processed);
+			}
+			metadata = processedMetadatas;
+		}
+
+		// Convenience for adding a single embedding.
 		public AddEmbeddingsRequest(String id, float[] embedding, Map<String, Object> metadata, String document) {
 			this(List.of(id), List.of(embedding), List.of(metadata), List.of(document));
 		}

vector-stores/spring-ai-chroma-store/src/test/java/org/springframework/ai/chroma/vectorstore/ChromaApiIT.java

@@ -43,6 +43,8 @@ import org.springframework.context.annotation.Bean;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.AssertionsForClassTypes.assertThatNoException;
 import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+import static net.javacrumbs.jsonunit.assertj.JsonAssertions.assertThatJson;
+import static net.javacrumbs.jsonunit.assertj.JsonAssertions.json;
 
 /**
  * @author Christian Tzolov
@@ -275,6 +277,22 @@ public class ChromaApiIT {
 					"Collection non-existent doesn't exist and won't be created as the initializeSchema is set to false.");
 	}
 
+	@Test
+	public void testAddEmbeddingsRequestMetadataConversion() {
+		Map<String, Object> metadata = Map.of("intVal", 42, "boolVal", true, "strVal", "hello", "doubleVal", 3.14,
+				"listVal", List.of(1, 2, 3), "mapVal", Map.of("a", 1, "b", 2));
+		AddEmbeddingsRequest req = new AddEmbeddingsRequest("id", new float[] { 1f, 2f, 3f }, metadata, "doc");
+		Map<String, Object> processed = req.metadata().get(0);
+
+		assertThat(processed.get("intVal")).isInstanceOf(Integer.class);
+		assertThat(processed.get("boolVal")).isInstanceOf(Boolean.class);
+		assertThat(processed.get("strVal")).isInstanceOf(String.class);
+		assertThat(processed.get("doubleVal")).isInstanceOf(Number.class).isEqualTo(3.14);
+		assertThat(processed.get("listVal")).isInstanceOf(String.class).isEqualTo("[1,2,3]");
+		assertThat(processed.get("mapVal")).isInstanceOf(String.class);
+		assertThatJson(processed.get("mapVal")).isEqualTo("{a:1,b:2}");
+	}
+
 	@SpringBootConfiguration
 	public static class Config {