diff --git a/src/external/database/serde/common.rs b/src/external/database/serde/common.rs
index e46b3de..07f085b 100644
--- a/src/external/database/serde/common.rs
+++ b/src/external/database/serde/common.rs
@@ -13,7 +13,7 @@ pub enum AlbumLibIdDef {
     None,
 }
 
-#[derive(Debug, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
 pub struct SerdeAlbumLibId(#[serde(with = "AlbumLibIdDef")] AlbumLibId);
 
 impl From<SerdeAlbumLibId> for AlbumLibId {
@@ -36,7 +36,7 @@ pub struct AlbumDateDef {
     day: Option<u8>,
 }
 
-#[derive(Debug, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
 pub struct SerdeAlbumDate(#[serde(with = "AlbumDateDef")] pub AlbumDate);
 
 impl From<SerdeAlbumDate> for AlbumDate {
@@ -69,7 +69,7 @@ pub enum AlbumPrimaryTypeDef {
     Other,
 }
 
-#[derive(Debug, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
 pub struct SerdeAlbumPrimaryType(#[serde(with = "AlbumPrimaryTypeDef")] AlbumPrimaryType);
 
 impl From<SerdeAlbumPrimaryType> for AlbumPrimaryType {
@@ -101,7 +101,7 @@ pub enum AlbumSecondaryTypeDef {
     FieldRecording,
 }
 
-#[derive(Debug, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
 pub struct SerdeAlbumSecondaryType(#[serde(with = "AlbumSecondaryTypeDef")] AlbumSecondaryType);
 
 impl From<SerdeAlbumSecondaryType> for AlbumSecondaryType {
diff --git a/src/external/database/serde/serialize.rs b/src/external/database/serde/serialize.rs
index aa9b336..197fc71 100644
--- a/src/external/database/serde/serialize.rs
+++ b/src/external/database/serde/serialize.rs
@@ -22,7 +22,7 @@ impl<'a> From<&'a Collection> for SerializeDatabase<'a> {
     }
 }
 
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, PartialEq, Eq)]
 pub struct SerializeArtist<'a> {
     pub name: &'a str,
     pub sort: Option<&'a str>,
@@ -31,7 +31,7 @@ pub struct SerializeArtist<'a> {
     pub albums: Vec<SerializeAlbum<'a>>,
 }
 
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, PartialEq, Eq)]
 pub struct SerializeAlbum<'a> {
     pub title: &'a str,
     pub lib_id: SerdeAlbumLibId,
@@ -42,12 +42,12 @@ pub struct SerializeAlbum<'a> {
     pub secondary_types: Vec<SerdeAlbumSecondaryType>,
 }
 
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, PartialEq, Eq)]
 pub struct SerializeMbRefOption<'a>(
     #[serde(with = "MbRefOptionDef")] MbRefOption<SerializeMbid<'a>>,
 );
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct SerializeMbid<'a>(&'a Mbid);
 
 impl<'a, T: IMusicBrainzRef> From<&'a MbRefOption<T>> for SerializeMbRefOption<'a> {
diff --git a/src/external/database/sql/mod.rs b/src/external/database/sql/mod.rs
index f215a5a..d442002 100644
--- a/src/external/database/sql/mod.rs
+++ b/src/external/database/sql/mod.rs
@@ -144,9 +144,9 @@ impl<SDB: for<'conn> ISqlDatabaseBackend<'conn>> SqlDatabase<SDB> {
     }
 
     fn drop_tables<Tx: ISqlTransactionBackend>(tx: &Tx) -> Result<(), Error> {
-        tx.drop_database_metadata_table()?;
-        tx.drop_artists_table()?;
         tx.drop_albums_table()?;
+        tx.drop_artists_table()?;
+        tx.drop_database_metadata_table()?;
         Ok(())
     }
 }
@@ -201,103 +201,186 @@ impl<SDB: for<'conn> ISqlDatabaseBackend<'conn>> IDatabase for SqlDatabase<SDB>
 // #[cfg(test)]
 // pub mod testmod;
 
-// #[cfg(test)]
-// mod tests {
-//     use std::collections::HashMap;
+#[cfg(test)]
+mod tests {
+    //     use std::collections::HashMap;
 
-//     use mockall::predicate;
+    use std::collections::VecDeque;
 
-//     use crate::core::{
-//         collection::{artist::Artist, Collection},
-//         testmod::FULL_COLLECTION,
-//     };
+    use mockall::{predicate, Sequence};
 
-//     use super::*;
-//     use testmod::DATABASE_JSON;
+    use crate::core::{
+        // collection::{artist::Artist, Collection},
+        testmod::FULL_COLLECTION,
+    };
 
-//     fn expected() -> Collection {
-//         let mut expected = FULL_COLLECTION.to_owned();
-//         for artist in expected.iter_mut() {
-//             for album in artist.albums.iter_mut() {
-//                 album.tracks.clear();
-//             }
-//         }
-//         expected
-//     }
+    use super::*;
 
-//     #[test]
-//     fn save() {
-//         let write_data = FULL_COLLECTION.to_owned();
-//         let input = DATABASE_JSON.to_owned();
+    //     fn expected() -> Collection {
+    //         let mut expected = FULL_COLLECTION.to_owned();
+    //         for artist in expected.iter_mut() {
+    //             for album in artist.albums.iter_mut() {
+    //                 album.tracks.clear();
+    //             }
+    //         }
+    //         expected
+    //     }
 
-//         let mut backend = MockISqlDatabaseBackend::new();
-//         backend
-//             .expect_write()
-//             .with(predicate::eq(input))
-//             .times(1)
-//             .return_once(|_| Ok(()));
+    struct SqlDatabaseTestBackend {
+        pub txs: VecDeque<MockISqlTransactionBackend>,
+    }
 
-//         SqlDatabase::new(backend).save(&write_data).unwrap();
-//     }
+    impl SqlDatabaseTestBackend {
+        fn new(txs: VecDeque<MockISqlTransactionBackend>) -> Self {
+            SqlDatabaseTestBackend { txs }
+        }
+    }
 
-//     #[test]
-//     fn load() {
-//         let expected = expected();
-//         let result = Ok(DATABASE_JSON.to_owned());
-//         eprintln!("{DATABASE_JSON}");
+    impl ISqlDatabaseBackend<'_> for SqlDatabaseTestBackend {
+        type Tx = MockISqlTransactionBackend;
 
-//         let mut backend = MockISqlDatabaseBackend::new();
-//         backend.expect_read().times(1).return_once(|| result);
+        fn transaction(&mut self) -> Result<Self::Tx, Error> {
+            Ok(self.txs.pop_front().unwrap())
+        }
+    }
 
-//         let read_data: Vec<Artist> = SqlDatabase::new(backend).load().unwrap();
+    macro_rules! then {
+        ($tx:ident, $seq:ident, $expect:ident) => {
+            $tx.$expect().times(1).in_sequence(&mut $seq)
+        };
+    }
 
-//         assert_eq!(read_data, expected);
-//     }
+    macro_rules! then0 {
+        ($tx:ident, $seq:ident, $expect:ident) => {
+            then!($tx, $seq, $expect).return_once(|| Ok(()))
+        };
+    }
 
-//     #[test]
-//     fn reverse() {
-//         let input = DATABASE_JSON.to_owned();
-//         let result = Ok(input.clone());
+    macro_rules! then1 {
+        ($tx:ident, $seq:ident, $expect:ident) => {
+            then!($tx, $seq, $expect).return_once(|_| Ok(()))
+        };
+    }
 
-//         let mut backend = MockISqlDatabaseBackend::new();
-//         backend
-//             .expect_write()
-//             .with(predicate::eq(input))
-//             .times(1)
-//             .return_once(|_| Ok(()));
-//         backend.expect_read().times(1).return_once(|| result);
-//         let mut database = SqlDatabase::new(backend);
+    macro_rules! then2 {
+        ($tx:ident, $seq:ident, $expect:ident) => {
+            then!($tx, $seq, $expect).return_once(|_, _| Ok(()))
+        };
+    }
 
-//         let write_data = FULL_COLLECTION.to_owned();
-//         database.save(&write_data).unwrap();
-//         let read_data: Vec<Artist> = database.load().unwrap();
+    macro_rules! expect_create {
+        ($tx:ident, $seq:ident) => {
+            let mut seq = Sequence::new();
+            then0!($tx, seq, expect_create_database_metadata_table);
+            then0!($tx, seq, expect_create_artists_table);
+            then0!($tx, seq, expect_create_albums_table);
+        };
+    }
 
-//         // Album information is not saved to disk.
-//         let expected = expected();
-//         assert_eq!(read_data, expected);
-//     }
+    macro_rules! expect_drop {
+        ($tx:ident, $seq:ident) => {
+            let mut seq = Sequence::new();
+            then0!($tx, seq, expect_drop_albums_table);
+            then0!($tx, seq, expect_drop_artists_table);
+            then0!($tx, seq, expect_drop_database_metadata_table);
+        };
+    }
 
-//     #[test]
-//     fn load_errors() {
-//         let json = String::from("");
-//         let serde_err = serde_json::from_str::<DeserializeDatabase>(&json);
-//         assert!(serde_err.is_err());
+    fn database(txs: VecDeque<MockISqlTransactionBackend>) -> SqlDatabase<SqlDatabaseTestBackend> {
+        let mut backend = SqlDatabaseTestBackend::new(txs);
+        let mut tx = MockISqlTransactionBackend::new();
 
-//         let serde_err: LoadError = serde_err.unwrap_err().into();
-//         assert!(!serde_err.to_string().is_empty());
-//         assert!(!format!("{:?}", serde_err).is_empty());
-//     }
+        let mut seq = Sequence::new();
+        expect_create!(tx, seq);
+        then0!(tx, seq, expect_commit);
 
-//     #[test]
-//     fn save_errors() {
-//         // serde_json will raise an error as it has certain requirements on keys.
-//         let mut object = HashMap::<Result<(), ()>, String>::new();
-//         object.insert(Ok(()), String::from("string"));
-//         let serde_err = serde_json::to_string(&object);
-//         assert!(serde_err.is_err());
+        backend.txs.push_front(tx);
+        SqlDatabase::new(backend).unwrap()
+    }
 
-//         let serde_err: SaveError = serde_err.unwrap_err().into();
-//         assert!(!serde_err.to_string().is_empty());
-//         assert!(!format!("{:?}", serde_err).is_empty());
-//     }
-// }
+    #[test]
+    fn save() {
+        let write_data = FULL_COLLECTION.to_owned();
+
+        let mut tx = MockISqlTransactionBackend::new();
+
+        let mut seq = Sequence::new();
+        expect_drop!(tx, seq);
+        expect_create!(tx, seq);
+        then1!(tx, seq, expect_insert_database_version).with(predicate::eq(V20250103));
+        for artist in write_data.iter() {
+            let ac = artist.clone();
+            then1!(tx, seq, expect_insert_artist)
+                .withf(move |a| a == &Into::<SerializeArtist>::into(&ac));
+            for album in artist.albums.iter() {
+                let (nc, ac) = (artist.meta.id.name.clone(), album.clone());
+                then2!(tx, seq, expect_insert_album)
+                    .withf(move |n, a| n == nc && a == &Into::<SerializeAlbum>::into(&ac));
+            }
+        }
+        then0!(tx, seq, expect_commit);
+
+        assert!(database(VecDeque::from([tx])).save(&write_data).is_ok());
+    }
+
+    //     #[test]
+    //     fn load() {
+    //         let expected = expected();
+    //         let result = Ok(DATABASE_JSON.to_owned());
+    //         eprintln!("{DATABASE_JSON}");
+
+    //         let mut backend = MockISqlDatabaseBackend::new();
+    //         backend.expect_read().times(1).return_once(|| result);
+
+    //         let read_data: Vec<Artist> = SqlDatabase::new(backend).load().unwrap();
+
+    //         assert_eq!(read_data, expected);
+    //     }
+
+    //     #[test]
+    //     fn reverse() {
+    //         let input = DATABASE_JSON.to_owned();
+    //         let result = Ok(input.clone());
+
+    //         let mut backend = MockISqlDatabaseBackend::new();
+    //         backend
+    //             .expect_write()
+    //             .with(predicate::eq(input))
+    //             .times(1)
+    //             .return_once(|_| Ok(()));
+    //         backend.expect_read().times(1).return_once(|| result);
+    //         let mut database = SqlDatabase::new(backend);
+
+    //         let write_data = FULL_COLLECTION.to_owned();
+    //         database.save(&write_data).unwrap();
+    //         let read_data: Vec<Artist> = database.load().unwrap();
+
+    //         // Album information is not saved to disk.
+    //         let expected = expected();
+    //         assert_eq!(read_data, expected);
+    //     }
+
+    //     #[test]
+    //     fn load_errors() {
+    //         let json = String::from("");
+    //         let serde_err = serde_json::from_str::<DeserializeDatabase>(&json);
+    //         assert!(serde_err.is_err());
+
+    //         let serde_err: LoadError = serde_err.unwrap_err().into();
+    //         assert!(!serde_err.to_string().is_empty());
+    //         assert!(!format!("{:?}", serde_err).is_empty());
+    //     }
+
+    //     #[test]
+    //     fn save_errors() {
+    //         // serde_json will raise an error as it has certain requirements on keys.
+    //         let mut object = HashMap::<Result<(), ()>, String>::new();
+    //         object.insert(Ok(()), String::from("string"));
+    //         let serde_err = serde_json::to_string(&object);
+    //         assert!(serde_err.is_err());
+
+    //         let serde_err: SaveError = serde_err.unwrap_err().into();
+    //         assert!(!serde_err.to_string().is_empty());
+    //         assert!(!format!("{:?}", serde_err).is_empty());
+    //     }
+}