chore: increasing mini sprite core tests

.github/workflows/mini_sprite.yaml

@@ -43,4 +43,4 @@ jobs:
         uses: VeryGoodOpenSource/very_good_coverage@v1
         with:
           path: packages/mini_sprite/coverage/lcov.info
-          min_coverage: 60
+          min_coverage: 100

packages/mini_sprite/test/src/mini_map_test.dart

@@ -0,0 +1,37 @@
+import 'package:mini_sprite/mini_sprite.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('MiniMap', () {
+    test('fromDataString returns the correct instance', () {
+      const data = '[{"x": 0, "y": 0, "data": {"sprite": "player"}}]';
+      final instance = MiniMap.fromDataString(data);
+
+      expect(
+        instance,
+        MiniMap(
+          objects: {
+            const MapPosition(0, 0): const <String, dynamic>{
+              'sprite': 'player',
+            },
+          },
+        ),
+      );
+    });
+
+    test('toDataString returns the correct serialized data', () {
+      const data = '[{"x":0,"y":0,"data":{"sprite":"player"}}]';
+
+      expect(
+        MiniMap(
+          objects: {
+            const MapPosition(0, 0): const <String, dynamic>{
+              'sprite': 'player',
+            },
+          },
+        ).toDataString(),
+        equals(data),
+      );
+    });
+  });
+}