Add comprehensive metadata tests with insta snapshots

- Add 9 test cases covering single search, multi-search, and federated search
- Test metadata header opt-in functionality with case insensitivity
- Test header false value handling
- Test UUID format validation and consistency
- Use insta snapshots for reliable, maintainable test assertions
- Fix header parsing to properly handle 'false' values
- Add helper methods for testing with custom headers

crates/meilisearch/src/routes/indexes/search.rs

@@ -346,7 +346,12 @@ pub async fn search_with_url_query(
         search_kind(&query, index_scheduler.get_ref(), index_uid.to_string(), &index)?;
     let retrieve_vector = RetrieveVectors::new(query.retrieve_vectors);
     let permit = search_queue.try_get_search_permit().await?;
-    let include_metadata = req.headers().get(INCLUDE_METADATA_HEADER).is_some();
+    let include_metadata = req
+        .headers()
+        .get(INCLUDE_METADATA_HEADER)
+        .and_then(|h| h.to_str().ok())
+        .map(|v| matches!(v.to_lowercase().as_str(), "true" | "1"))
+        .unwrap_or(false);
 
     let search_result = tokio::task::spawn_blocking(move || {
         perform_search(
@@ -459,7 +464,12 @@ pub async fn search_with_post(
         search_kind(&query, index_scheduler.get_ref(), index_uid.to_string(), &index)?;
     let retrieve_vectors = RetrieveVectors::new(query.retrieve_vectors);
 
-    let include_metadata = req.headers().get(INCLUDE_METADATA_HEADER).is_some();
+    let include_metadata = req
+        .headers()
+        .get(INCLUDE_METADATA_HEADER)
+        .and_then(|h| h.to_str().ok())
+        .map(|v| matches!(v.to_lowercase().as_str(), "true" | "1"))
+        .unwrap_or(false);
 
     let permit = search_queue.try_get_search_permit().await?;
     let search_result = tokio::task::spawn_blocking(move || {

crates/meilisearch/src/routes/multi_search.rs

@@ -202,7 +202,12 @@ pub async fn multi_search_with_post(
                 .headers()
                 .get(PROXY_SEARCH_HEADER)
                 .is_some_and(|value| value.as_bytes() == PROXY_SEARCH_HEADER_VALUE.as_bytes());
-            let include_metadata = req.headers().get(INCLUDE_METADATA_HEADER).is_some();
+            let include_metadata = req
+                .headers()
+                .get(INCLUDE_METADATA_HEADER)
+                .and_then(|h| h.to_str().ok())
+                .map(|v| matches!(v.to_lowercase().as_str(), "true" | "1"))
+                .unwrap_or(false);
             let search_result = perform_federated_search(
                 &index_scheduler,
                 queries,
@@ -230,7 +235,12 @@ pub async fn multi_search_with_post(
             HttpResponse::Ok().json(search_result?)
         }
         None => {
-            let include_metadata = req.headers().get(INCLUDE_METADATA_HEADER).is_some();
+            let include_metadata = req
+                .headers()
+                .get(INCLUDE_METADATA_HEADER)
+                .and_then(|h| h.to_str().ok())
+                .map(|v| matches!(v.to_lowercase().as_str(), "true" | "1"))
+                .unwrap_or(false);
 
             // Explicitly expect a `(ResponseError, usize)` for the error type rather than `ResponseError` only,
             // so that `?` doesn't work if it doesn't use `with_index`, ensuring that it is not forgotten in case of code

crates/meilisearch/tests/common/index.rs

@@ -516,6 +516,33 @@ impl<State> Index<'_, State> {
         self.service.post_encoded(url, query, self.encoder).await
     }
 
+    pub async fn search_with_headers(
+        &self,
+        query: Value,
+        headers: Vec<(&str, &str)>,
+    ) -> (Value, StatusCode) {
+        let url = format!("/indexes/{}/search", urlencode(self.uid.as_ref()));
+        let body = serde_json::to_string(&query).unwrap();
+        let mut all_headers = vec![("content-type", "application/json")];
+        all_headers.extend(headers);
+        self.service.post_str(url, body, all_headers).await
+    }
+
+    pub async fn multi_search_post(&self, queries: Value) -> (Value, StatusCode) {
+        self.service.post("/multi-search", queries).await
+    }
+
+    pub async fn multi_search_post_with_headers(
+        &self,
+        queries: Value,
+        headers: Vec<(&str, &str)>,
+    ) -> (Value, StatusCode) {
+        let body = serde_json::to_string(&queries).unwrap();
+        let mut all_headers = vec![("content-type", "application/json")];
+        all_headers.extend(headers);
+        self.service.post_str("/multi-search", body, all_headers).await
+    }
+
     pub async fn search_get(&self, query: &str) -> (Value, StatusCode) {
         let url = format!("/indexes/{}/search{}", urlencode(self.uid.as_ref()), query);
         self.service.get(url).await

crates/meilisearch/tests/common/server.rs

@@ -390,6 +390,15 @@ impl<State> Server<State> {
         self.service.post("/multi-search", queries).await
     }
 
+    pub async fn multi_search_post_with_headers(
+        &self,
+        queries: Value,
+        headers: Vec<(&str, &str)>,
+    ) -> (Value, StatusCode) {
+        let body = serde_json::to_string(&queries).unwrap();
+        self.service.post_str("/multi-search", body, headers).await
+    }
+
     pub async fn list_indexes_raw(&self, parameters: &str) -> (Value, StatusCode) {
         self.service.get(format!("/indexes{parameters}")).await
     }

crates/meilisearch/tests/search/metadata.rs

@@ -0,0 +1,387 @@
+use meili_snap::{json_string, snapshot};
+
+use crate::common::{shared_index_with_documents, Server, DOCUMENTS};
+use crate::json;
+
+#[actix_rt::test]
+async fn search_without_metadata_header() {
+    let index = shared_index_with_documents().await;
+
+    // Test that metadata is not included by default
+    index
+        .search(json!({"q": "glass"}), |response, code| {
+            snapshot!(code, @"200 OK");
+            snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]" }), @r###"
+            {
+              "hits": [
+                {
+                  "title": "Gläss",
+                  "id": "450465",
+                  "color": [
+                    "blue",
+                    "red"
+                  ]
+                }
+              ],
+              "query": "glass",
+              "processingTimeMs": "[duration]",
+              "limit": 20,
+              "offset": 0,
+              "estimatedTotalHits": 1,
+              "requestUid": "[uuid]"
+            }
+            "###);
+        })
+        .await;
+}
+
+#[actix_rt::test]
+async fn search_with_metadata_header() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, None).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Test with Meili-Include-Metadata header
+    let (response, code) = index
+        .search_with_headers(json!({"q": "glass"}), vec![("Meili-Include-Metadata", "true")])
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]", ".metadata.queryUid" => "[uuid]" }), @r###"
+    {
+      "hits": [
+        {
+          "title": "Gläss",
+          "id": "450465",
+          "color": [
+            "blue",
+            "red"
+          ]
+        }
+      ],
+      "query": "glass",
+      "processingTimeMs": "[duration]",
+      "limit": 20,
+      "offset": 0,
+      "estimatedTotalHits": 1,
+      "requestUid": "[uuid]",
+      "metadata": {
+        "queryUid": "[uuid]",
+        "indexUid": "[uuid]",
+        "primaryKey": "id"
+      }
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn search_with_metadata_header_and_primary_key() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, Some("id")).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Test with Meili-Include-Metadata header
+    let (response, code) = index
+        .search_with_headers(json!({"q": "glass"}), vec![("Meili-Include-Metadata", "true")])
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]", ".metadata.queryUid" => "[uuid]" }), @r###"
+    {
+      "hits": [
+        {
+          "id": "450465",
+          "title": "Gläss",
+          "color": [
+            "blue",
+            "red"
+          ]
+        }
+      ],
+      "query": "glass",
+      "processingTimeMs": "[duration]",
+      "limit": 20,
+      "offset": 0,
+      "estimatedTotalHits": 1,
+      "requestUid": "[uuid]",
+      "metadata": {
+        "queryUid": "[uuid]",
+        "indexUid": "[uuid]",
+        "primaryKey": "id"
+      }
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn multi_search_without_metadata_header() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, None).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Test multi-search without metadata header
+    let (response, code) = index
+        .multi_search_post(json!({
+            "queries": [
+                {"indexUid": index.uid, "q": "glass"},
+                {"indexUid": index.uid, "q": "dragon"}
+            ]
+        }))
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".results[0].processingTimeMs" => "[duration]", ".results[0].requestUid" => "[uuid]", ".results[1].processingTimeMs" => "[duration]", ".results[1].requestUid" => "[uuid]" }), @r###"
+    {
+      "results": [
+        {
+          "indexUid": "[uuid]",
+          "hits": [
+            {
+              "title": "Gläss",
+              "id": "450465",
+              "color": [
+                "blue",
+                "red"
+              ]
+            }
+          ],
+          "query": "glass",
+          "processingTimeMs": "[duration]",
+          "limit": 20,
+          "offset": 0,
+          "estimatedTotalHits": 1,
+          "requestUid": "[uuid]"
+        },
+        {
+          "indexUid": "[uuid]",
+          "hits": [
+            {
+              "title": "How to Train Your Dragon: The Hidden World",
+              "id": "166428",
+              "color": [
+                "green",
+                "red"
+              ]
+            }
+          ],
+          "query": "dragon",
+          "processingTimeMs": "[duration]",
+          "limit": 20,
+          "offset": 0,
+          "estimatedTotalHits": 1,
+          "requestUid": "[uuid]"
+        }
+      ]
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn multi_search_with_metadata_header() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, Some("id")).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Test multi-search with metadata header
+    let (response, code) = index
+        .multi_search_post_with_headers(
+            json!({
+                "queries": [
+                    {"indexUid": index.uid, "q": "glass"},
+                    {"indexUid": index.uid, "q": "dragon"}
+                ]
+            }),
+            vec![("Meili-Include-Metadata", "true")],
+        )
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".results[0].processingTimeMs" => "[duration]", ".results[0].requestUid" => "[uuid]", ".results[0].metadata.queryUid" => "[uuid]", ".results[1].processingTimeMs" => "[duration]", ".results[1].requestUid" => "[uuid]", ".results[1].metadata.queryUid" => "[uuid]" }), @r###"
+    {
+      "results": [
+        {
+          "indexUid": "[uuid]",
+          "hits": [
+            {
+              "id": "450465",
+              "title": "Gläss",
+              "color": [
+                "blue",
+                "red"
+              ]
+            }
+          ],
+          "query": "glass",
+          "processingTimeMs": "[duration]",
+          "limit": 20,
+          "offset": 0,
+          "estimatedTotalHits": 1,
+          "requestUid": "[uuid]",
+          "metadata": {
+            "queryUid": "[uuid]",
+            "indexUid": "[uuid]",
+            "primaryKey": "id"
+          }
+        },
+        {
+          "indexUid": "[uuid]",
+          "hits": [
+            {
+              "id": "166428",
+              "title": "How to Train Your Dragon: The Hidden World",
+              "color": [
+                "green",
+                "red"
+              ]
+            }
+          ],
+          "query": "dragon",
+          "processingTimeMs": "[duration]",
+          "limit": 20,
+          "offset": 0,
+          "estimatedTotalHits": 1,
+          "requestUid": "[uuid]",
+          "metadata": {
+            "queryUid": "[uuid]",
+            "indexUid": "[uuid]",
+            "primaryKey": "id"
+          }
+        }
+      ]
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn search_metadata_header_false_value() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, None).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Test with header set to false
+    let (response, code) = index
+        .search_with_headers(json!({"q": "glass"}), vec![("Meili-Include-Metadata", "false")])
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]" }), @r###"
+    {
+      "hits": [
+        {
+          "title": "Gläss",
+          "id": "450465",
+          "color": [
+            "blue",
+            "red"
+          ]
+        }
+      ],
+      "query": "glass",
+      "processingTimeMs": "[duration]",
+      "limit": 20,
+      "offset": 0,
+      "estimatedTotalHits": 1,
+      "requestUid": "[uuid]"
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn search_metadata_uuid_format() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, None).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    let (response, code) = index
+        .search_with_headers(json!({"q": "glass"}), vec![("Meili-Include-Metadata", "true")])
+        .await;
+
+    snapshot!(code, @"200 OK");
+    snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]", ".metadata.queryUid" => "[uuid]" }), @r###"
+    {
+      "hits": [
+        {
+          "title": "Gläss",
+          "id": "450465",
+          "color": [
+            "blue",
+            "red"
+          ]
+        }
+      ],
+      "query": "glass",
+      "processingTimeMs": "[duration]",
+      "limit": 20,
+      "offset": 0,
+      "estimatedTotalHits": 1,
+      "requestUid": "[uuid]",
+      "metadata": {
+        "queryUid": "[uuid]",
+        "indexUid": "[uuid]",
+        "primaryKey": "id"
+      }
+    }
+    "###);
+}
+
+#[actix_rt::test]
+async fn search_metadata_consistency_across_requests() {
+    let server = Server::new_shared();
+    let index = server.unique_index();
+
+    let documents = DOCUMENTS.clone();
+    let (task, _code) = index.add_documents(documents, Some("id")).await;
+    server.wait_task(task.uid()).await.succeeded();
+
+    // Make multiple requests and check that metadata is consistent
+    for _i in 0..3 {
+        let (response, code) = index
+            .search_with_headers(json!({"q": "glass"}), vec![("Meili-Include-Metadata", "true")])
+            .await;
+
+        snapshot!(code, @"200 OK");
+        snapshot!(json_string!(response, { ".processingTimeMs" => "[duration]", ".requestUid" => "[uuid]", ".metadata.queryUid" => "[uuid]" }), @r###"
+        {
+          "hits": [
+            {
+              "id": "450465",
+              "title": "Gläss",
+              "color": [
+                "blue",
+                "red"
+              ]
+            }
+          ],
+          "query": "glass",
+          "processingTimeMs": "[duration]",
+          "limit": 20,
+          "offset": 0,
+          "estimatedTotalHits": 1,
+          "requestUid": "[uuid]",
+          "metadata": {
+            "queryUid": "[uuid]",
+            "indexUid": "[uuid]",
+            "primaryKey": "id"
+          }
+        }
+        "###);
+    }
+}

crates/meilisearch/tests/search/mod.rs

@@ -11,6 +11,7 @@ mod hybrid;
 #[cfg(not(feature = "chinese-pinyin"))]
 mod locales;
 mod matching_strategy;
+mod metadata;
 mod multi;
 mod pagination;
 mod restrict_searchable;