Fix OpenSearchVectorStoreIT

 - Explicitly invoke OpenSearchVectorStore's afterPropertiesSet to make sure index mapping is completed.

Signed-off-by: Ilayaperumal Gopinathan <ilayaperumal.gopinathan@broadcom.com>

Author: ilayaperumalg

vector-stores/spring-ai-opensearch-store/src/test/java/org/springframework/ai/vectorstore/opensearch/OpenSearchVectorStoreIT.java

@@ -825,6 +825,9 @@ void testManageDocumentIdsSetting(boolean manageDocumentIds) {
 				.initializeSchema(true)
 				.build();
 
+			// Ensure the index is fully initialized before adding documents
+			testVectorStore.afterPropertiesSet();
+
 			// Test documents
 			List<Document> testDocuments = List.of(new Document("doc1", "Test content 1", Map.of("key1", "value1")),
 					new Document("doc2", "Test content 2", Map.of("key2", "value2")));
@@ -870,6 +873,9 @@ void testManageDocumentIdsFalseForAWSOpenSearchServerless() {
 				.initializeSchema(true)
 				.build();
 
+			// Ensure the index is fully initialized before adding documents
+			awsCompatibleVectorStore.afterPropertiesSet();
+
 			// Test documents with IDs (these should be ignored when
 			// manageDocumentIds=false)
 			List<Document> testDocuments = List.of(
@@ -917,6 +923,9 @@ void testManageDocumentIdsTrueWithExplicitIds() {
 				.initializeSchema(true)
 				.build();
 
+			// Ensure the index is fully initialized before adding documents
+			explicitIdVectorStore.afterPropertiesSet();
+
 			// Test documents with specific IDs
 			List<Document> testDocuments = List.of(
 					new Document("explicit-id-1", "Explicit ID content 1", Map.of("type", "explicit")),