db test: Cover simple migrations without data programmatically

This saves us from writing the simple migration tests between schemas
without data in the future.

---

The tests are inspired by the test template generated from
`dart run drift_dev make-migrations`.

To reproduce the outputs, go through the following steps:

Modify `build.yaml` by specifying the location of the database. This
step is needed because `make-migrations` does not accept this through
command line arguments.

```
targets:
  $default:
    builders:
      # ...
      drift_dev:
        options:
          databases:
            default: lib/model/database.dart
```

Then, run the following commands:

```
dart run drift_dev make-migrations
cp test/model/schemas/*.json drift_schemas/default/
dart run drift_dev make-migrations
```

The first `make-migrations` run generates the initial schema and test
files without looking at the versions we have in test/model/schemas.

Copying the schema files and running `make-migrations` will end up
creating `test/drift/default/migration_test.dart`, along with other
generated files.

See also:
  https://drift.simonbinder.eu/Migrations/#usage

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

test/model/database_test.dart

@@ -98,11 +98,30 @@ void main() {
       verifier = SchemaVerifier(GeneratedHelper());
     });
 
-    test('upgrade to v2, empty', () async {
-      final connection = await verifier.startAt(1);
-      final db = AppDatabase(connection);
-      await verifier.migrateAndValidate(db, 2);
-      await db.close();
+    group('migrate without data', () {
+      const versions = GeneratedHelper.versions;
+      final latestVersion = versions.last;
+
+      int fromVersion = versions.first;
+      for (final toVersion in versions.skip(1)) {
+        test('from v$fromVersion to v$toVersion', () async {
+          final connection = await verifier.startAt(fromVersion!);
+          final db = AppDatabase(connection);
+          await verifier.migrateAndValidate(db, toVersion);
+          await db.close();
+        });
+        fromVersion = toVersion;
+      }
+
+      for (final fromVersion in versions) {
+        if (fromVersion == latestVersion) break;
+        test('from v$fromVersion to latest (v$latestVersion)', () async {
+          final connection = await verifier.startAt(fromVersion);
+          final db = AppDatabase(connection);
+          await verifier.migrateAndValidate(db, latestVersion);
+          await db.close();
+        });
+      }
     });
 
     test('upgrade to v2, with data', () async {