Improve the test to check that we do not delete more than necessary

Author: Kerollmops

src/tests/writer.rs

@@ -4,7 +4,7 @@ use rand::Rng;
 
 use super::{create_database, rng};
 use crate::distance::{DotProduct, Euclidean};
-use crate::{Database, Writer};
+use crate::{Database, Reader, Writer};
 
 #[test]
 fn clear_small_database() {
@@ -15,15 +15,23 @@ fn clear_small_database() {
 
     let mut wtxn = env.write_txn().unwrap();
     let database: Database<DotProduct> = env.create_database(&mut wtxn, None).unwrap();
-    let writer = Writer::new(database, 0, 3);
-    writer.add_item(&mut wtxn, 0, &[0.0, 1.0, 2.0]).unwrap();
-    writer.clear(&mut wtxn).unwrap();
-    writer.build(&mut wtxn, &mut rng(), None).unwrap();
+
+    let zero_writer = Writer::new(database, 0, 3);
+    zero_writer.add_item(&mut wtxn, 0, &[0.0, 1.0, 2.0]).unwrap();
+    zero_writer.clear(&mut wtxn).unwrap();
+    zero_writer.build(&mut wtxn, &mut rng(), None).unwrap();
+
+    let one_writer = Writer::new(database, 1, 3);
+    one_writer.add_item(&mut wtxn, 0, &[1.0, 2.0, 3.0]).unwrap();
+    one_writer.build(&mut wtxn, &mut rng(), None).unwrap();
     wtxn.commit().unwrap();
 
     let mut wtxn = env.write_txn().unwrap();
-    let writer = Writer::new(database, 0, 3);
-    writer.clear(&mut wtxn).unwrap();
+    let zero_writer = Writer::new(database, 0, 3);
+    zero_writer.clear(&mut wtxn).unwrap();
+
+    let one_reader = Reader::open(&wtxn, 1, database).unwrap();
+    assert_eq!(one_reader.item_vector(&wtxn, 0).unwrap().unwrap(), vec![1.0, 2.0, 3.0]);
     wtxn.commit().unwrap();
 }