diff --git a/pttodoer/src/main.rs b/pttodoer/src/main.rs
index d00235d..a52adc3 100644
--- a/pttodoer/src/main.rs
+++ b/pttodoer/src/main.rs
@@ -92,7 +92,8 @@ mod test_taskss {
 
    #[test]
    fn read_single_file() {
-      _ = DB::new("./src/testdata/taskss.d/single_file.yaml".to_string()).expect("failed to construct from single file");
+      let db = DB::new("./src/testdata/taskss.d/single_file.yaml".to_string()).expect("failed to construct from single file");
+      assert_eq!(1, db.0.len());
    }
 }