diff --git a/file-service/src/store/mod.rs b/file-service/src/store/mod.rs
index 227d8bb..9975788 100644
--- a/file-service/src/store/mod.rs
+++ b/file-service/src/store/mod.rs
@@ -116,18 +116,19 @@ impl Store {
 
     pub fn list_files(&self) -> Result<HashSet<FileId>, ReadFileError> {
         let paths = std::fs::read_dir(&self.files_root)?;
-        Ok(paths
+        let info_files = paths
             .into_iter()
-            .map(|path| {
-                FileId::from(
-                    path.unwrap()
-                        .path()
-                        .file_stem()
-                        .and_then(|s| s.to_str())
-                        .unwrap(),
-                )
+            .filter_map(|path| {
+                let path_ = path.unwrap().path();
+                if path_.extension().and_then(|s| s.to_str()) == Some("json") {
+                    let stem = path_.file_stem().and_then(|s| s.to_str()).unwrap();
+                    Some(FileId::from(FileId::from(stem)))
+                } else {
+                    None
+                }
             })
-            .collect::<HashSet<FileId>>())
+            .collect::<HashSet<FileId>>();
+        Ok(info_files)
     }
 
     pub fn add_file(
@@ -237,6 +238,7 @@ mod test {
 
             println!("ids: {:?}", ids);
             assert_eq!(ids.len(), 1);
+            assert!(ids.contains(&id));
         });
     }
 }