Get from disk

Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["William Speirs <bill.speirs@gmail.com>"]
 
 [dependencies]
-rand = "*"
+rand = "0.5.0"
 bincode = "0.6.0"
 rustc-serialize = "0.3.19"
 itertools = "0.5.5"

src/lib.rs

@@ -49,7 +49,7 @@ impl <K: KeyType, V: ValueType> BTree<K, V> {
         let mut wal_file = try!(RecordFile::<K,V>::new(&wal_file_path, key_size, value_size));
 
         // if we have a WAL file, replay it into the mem_tree
-        if try!(wal_file.is_new()) {
+        if !try!(wal_file.is_new()) {
             for kv in &mut wal_file {
                 mem_tree.insert(kv.key, kv.value);
             }
@@ -204,10 +204,6 @@ mod tests {
         // setup tree
         let mut btree = BTree::<String, String>::new(&file_path, 15, 15).unwrap();
 
-        // expected return set
-        let mut expected: BTreeSet<String> = BTreeSet::new();
-        expected.insert("World".to_string());
-
         btree.insert("Hello".to_owned(), "World".to_owned());
 
         // get the set at the hello key
@@ -218,6 +214,26 @@ mod tests {
         remove_files(file_path); // remove files assuming it all went well
     }
 
+    #[test]
+    fn get_from_disk() {
+        let file_path = gen_temp_name();
+
+        // setup tree
+        let mut btree = BTree::<String, String>::new(&file_path, 15, 15).unwrap();
+        btree.insert("Hello".to_owned(), "World".to_owned());
+
+        // drop the btree and create a new one to ensure the `get` below happens from disk rather than cache
+        drop(btree);
+        let btree = BTree::<String, String>::new(&file_path, 15, 15).unwrap();
+
+        // get the set at the hello key
+        let set_at_hello: Vec<String> = btree.get(&"Hello".to_string()).expect("should read data").cloned().collect();
+
+        assert_eq!(set_at_hello, ["World".to_string()]);
+
+        remove_files(file_path); // remove files assuming it all went well
+    }
+
     #[test]
     fn insert_multiple() {
         let file_path = gen_temp_name();

src/wal_file.rs

@@ -165,4 +165,40 @@ mod tests {
 
         fs::remove_file(&file_path);
     }
+
+    #[test]
+    fn load_from_disk() {
+        let temp_path = gen_temp_name();
+        let file_path = temp_path.to_owned() + ".wal";
+
+        // create a new blank file
+        let mut wal_file = RecordFile::new(&file_path, 20, 20).unwrap();
+        assert!(wal_file.is_new().unwrap());
+
+        let kv1 = KeyValuePair{key: "hello".to_owned(), value: "world".to_owned()};
+        let kv2 = KeyValuePair{key: "foo".to_owned(), value: "bar".to_owned()};
+
+        wal_file.insert_record(&kv1).unwrap();
+        wal_file.insert_record(&kv2).unwrap();
+
+        // drop the above wal_file and create a new one
+        drop(wal_file);
+        let mut wal_file : RecordFile<String, String> = RecordFile::new(&file_path, 20, 20).unwrap();
+
+        assert!(wal_file.count().unwrap() == 2);
+
+        let mut wal_it = wal_file.into_iter();
+
+        let it_kv1 = wal_it.next().unwrap();
+
+        assert!(kv1.key == it_kv1.key);
+        assert!(kv1.value == it_kv1.value);
+
+        let it_kv2 = wal_it.next().unwrap();
+
+        assert!(kv2.key == it_kv2.key);
+        assert!(kv2.value == it_kv2.value);
+
+        fs::remove_file(&file_path);
+    }
 }