add test_share_reader

lib/src/db.rs

@@ -504,4 +504,40 @@ mod test {
             assert_eq!(pair.0, pair.1);
         });
     }
+
+    /// sharing Reader instance between threads
+    #[test]
+    fn test_share_reader() {
+        use std::thread;
+
+        let dir = tempdir().expect("tempdir");
+        let tmpfile = dir.path().join("test.tmp");
+        let opts = WriterOpts {
+            compress_lvl: 1,
+            data_buf_size: 10 * 1024 * 1024,
+            out_buf_size: 10 * 1024 * 1024,
+            current_buf_size: 4096,
+        };
+        let mut writer: Writer<TestData> = Writer::new(&tmpfile, opts).expect("new writer");
+
+        let items_iter = gen_data(10);
+        let items: Vec<TestData> = items_iter.collect();
+
+        writer.load(&mut items.clone().into_iter()).expect("load");
+        writer.finish().expect("finish write");
+
+        let reader: Reader<TestData> = Reader::new(&tmpfile, 2048).expect("new reader");
+        assert_eq!(items.len(), reader.len());
+
+        let reader = Arc::new(reader);
+        for _ in 0..=3 {
+            let cur_items = items.clone();
+            let cur_reader = Arc::clone(&reader);
+            thread::spawn(move || {
+                cur_items.into_iter().zip(cur_reader.iter()).for_each(|pair| {
+                    assert_eq!(pair.0, pair.1);
+                });
+            });
+        }
+    }
 }