create file for tests

src/test/java/MainFrameTest.java

@@ -1,7 +1,13 @@
 import org.junit.jupiter.api.*;
+import src.Model;
+
 import static org.junit.jupiter.api.Assertions.*;
 
 public class MainFrameTest {
 
+    @Test
+    public void test_initFile(){
+        Model.initJsonFile();
+    }
 
 }