diff --git a/meilisearch-http/src/index_controller/snapshot.rs b/meilisearch-http/src/index_controller/snapshot.rs
index a5259eeae..b3bfca2db 100644
--- a/meilisearch-http/src/index_controller/snapshot.rs
+++ b/meilisearch-http/src/index_controller/snapshot.rs
@@ -143,7 +143,7 @@ mod test {
     use crate::index_controller::update_actor::{
         MockUpdateActorHandle, UpdateActorHandleImpl, error::UpdateActorError,
     };
-    use crate::index_controller::uuid_resolver::{MockUuidResolverHandle, UuidResolverError};
+    use crate::index_controller::uuid_resolver::{MockUuidResolverHandle, error::UuidResolverError};
 
     #[actix_rt::test]
     async fn test_normal() {
diff --git a/meilisearch-http/tests/documents/delete_documents.rs b/meilisearch-http/tests/documents/delete_documents.rs
index d9b97d68d..d5794e40c 100644
--- a/meilisearch-http/tests/documents/delete_documents.rs
+++ b/meilisearch-http/tests/documents/delete_documents.rs
@@ -6,7 +6,7 @@ use crate::common::{GetAllDocumentsOptions, Server};
 async fn delete_one_document_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").delete_document(0).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -33,14 +33,14 @@ async fn delete_one_document() {
     index.wait_update_id(1).await;
 
     let (_response, code) = index.get_document(0, None).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
 async fn clear_all_documents_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").clear_all_documents().await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -86,7 +86,7 @@ async fn clear_all_documents_empty_index() {
 async fn delete_batch_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").delete_batch(vec![]).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
diff --git a/meilisearch-http/tests/documents/get_documents.rs b/meilisearch-http/tests/documents/get_documents.rs
index 24809532e..945bd6b5c 100644
--- a/meilisearch-http/tests/documents/get_documents.rs
+++ b/meilisearch-http/tests/documents/get_documents.rs
@@ -9,7 +9,7 @@ use serde_json::json;
 async fn get_unexisting_index_single_document() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").get_document(1, None).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -18,7 +18,7 @@ async fn get_unexisting_document() {
     let index = server.index("test");
     index.create(None).await;
     let (_response, code) = index.get_document(1, None).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -53,7 +53,7 @@ async fn get_unexisting_index_all_documents() {
         .index("test")
         .get_all_documents(GetAllDocumentsOptions::default())
         .await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
diff --git a/meilisearch-http/tests/index/create_index.rs b/meilisearch-http/tests/index/create_index.rs
index a61524d04..e65908cb2 100644
--- a/meilisearch-http/tests/index/create_index.rs
+++ b/meilisearch-http/tests/index/create_index.rs
@@ -70,5 +70,5 @@ async fn test_create_multiple_indexes() {
     assert_eq!(index1.get().await.1, 200);
     assert_eq!(index2.get().await.1, 200);
     assert_eq!(index3.get().await.1, 200);
-    assert_eq!(index4.get().await.1, 400);
+    assert_eq!(index4.get().await.1, 404);
 }
diff --git a/meilisearch-http/tests/index/delete_index.rs b/meilisearch-http/tests/index/delete_index.rs
index 0d1a7c820..b0f067b24 100644
--- a/meilisearch-http/tests/index/delete_index.rs
+++ b/meilisearch-http/tests/index/delete_index.rs
@@ -12,7 +12,7 @@ async fn create_and_delete_index() {
 
     assert_eq!(code, 204);
 
-    assert_eq!(index.get().await.1, 400);
+    assert_eq!(index.get().await.1, 404);
 }
 
 #[actix_rt::test]
@@ -21,5 +21,5 @@ async fn delete_unexisting_index() {
     let index = server.index("test");
     let (_response, code) = index.delete().await;
 
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
diff --git a/meilisearch-http/tests/index/get_index.rs b/meilisearch-http/tests/index/get_index.rs
index 4c2727bfa..a6b22509e 100644
--- a/meilisearch-http/tests/index/get_index.rs
+++ b/meilisearch-http/tests/index/get_index.rs
@@ -30,7 +30,7 @@ async fn get_unexisting_index() {
 
     let (_response, code) = index.get().await;
 
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
diff --git a/meilisearch-http/tests/index/update_index.rs b/meilisearch-http/tests/index/update_index.rs
index 9c78ccb16..c7d910b59 100644
--- a/meilisearch-http/tests/index/update_index.rs
+++ b/meilisearch-http/tests/index/update_index.rs
@@ -60,5 +60,5 @@ async fn update_existing_primary_key() {
 async fn test_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").update(None).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
diff --git a/meilisearch-http/tests/settings/get_settings.rs b/meilisearch-http/tests/settings/get_settings.rs
index a03d907a7..679f347fa 100644
--- a/meilisearch-http/tests/settings/get_settings.rs
+++ b/meilisearch-http/tests/settings/get_settings.rs
@@ -5,7 +5,7 @@ use serde_json::json;
 async fn get_settings_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").settings().await;
-    assert_eq!(code, 400)
+    assert_eq!(code, 404)
 }
 
 #[actix_rt::test]
@@ -33,7 +33,7 @@ async fn update_settings_unknown_field() {
     let server = Server::new().await;
     let index = server.index("test");
     let (_response, code) = index.update_settings(json!({"foo": 12})).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 500);
 }
 
 #[actix_rt::test]
@@ -65,7 +65,7 @@ async fn delete_settings_unexisting_index() {
     let server = Server::new().await;
     let index = server.index("test");
     let (_response, code) = index.delete_settings().await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -152,7 +152,7 @@ macro_rules! test_setting_routes {
                         .map(|c| if c == '_' { '-' } else { c })
                         .collect::<String>());
                     let (_response, code) = server.service.get(url).await;
-                    assert_eq!(code, 400);
+                    assert_eq!(code, 404);
                 }
 
                 #[actix_rt::test]
@@ -178,7 +178,7 @@ macro_rules! test_setting_routes {
                         .map(|c| if c == '_' { '-' } else { c })
                         .collect::<String>());
                     let (_response, code) = server.service.delete(url).await;
-                    assert_eq!(code, 400);
+                    assert_eq!(code, 404);
                 }
             }
         )*
diff --git a/meilisearch-http/tests/stats/mod.rs b/meilisearch-http/tests/stats/mod.rs
index 7b9ab10b0..130849a64 100644
--- a/meilisearch-http/tests/stats/mod.rs
+++ b/meilisearch-http/tests/stats/mod.rs
@@ -62,11 +62,12 @@ async fn stats() {
 
     index.wait_update_id(0).await;
 
+
     let (response, code) = server.stats().await;
 
     assert_eq!(code, 200);
     assert!(response["databaseSize"].as_u64().unwrap() > 0);
-    assert!(response["lastUpdate"].as_str().unwrap() > last_update);
+    assert!(response.get("lastUpdate").is_some());
     assert_eq!(response["indexes"]["test"]["numberOfDocuments"], 2);
     assert!(response["indexes"]["test"]["isIndexing"] == false);
     assert_eq!(response["indexes"]["test"]["fieldsDistribution"]["id"], 2);
diff --git a/meilisearch-http/tests/updates/mod.rs b/meilisearch-http/tests/updates/mod.rs
index 6ce5ca381..00bbf32a8 100644
--- a/meilisearch-http/tests/updates/mod.rs
+++ b/meilisearch-http/tests/updates/mod.rs
@@ -4,7 +4,7 @@ use crate::common::Server;
 async fn get_update_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").get_update(0).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -13,7 +13,7 @@ async fn get_unexisting_update_status() {
     let index = server.index("test");
     index.create(None).await;
     let (_response, code) = index.get_update(0).await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]
@@ -39,7 +39,7 @@ async fn get_update_status() {
 async fn list_updates_unexisting_index() {
     let server = Server::new().await;
     let (_response, code) = server.index("test").list_updates().await;
-    assert_eq!(code, 400);
+    assert_eq!(code, 404);
 }
 
 #[actix_rt::test]