feat: add test for appflowy_editor path (#1926)

frontend/appflowy_flutter/packages/appflowy_editor/test/core/document/path_test.dart

@@ -29,5 +29,43 @@ void main() async {
       expect(p2 <= p1, true);
       expect(p1.equals(p2), true);
     });
+    test(
+      "test path next, previous and parent getters",
+      () {
+        var p1 = [0, 0];
+        var p2 = [0, 1];
+
+        expect(p1.next.equals(p2), true);
+        expect(p1.previous.equals(p2), false);
+        expect(p1.parent.equals(p2), false);
+
+        p1 = [0, 1, 0];
+        p2 = [0, 1, 1];
+
+        expect(p2.next.equals(p1), false);
+        expect(p2.previous.equals(p1), true);
+        expect(p2.parent.equals(p1), false);
+
+        p1 = [0, 1, 1];
+        p2 = [0, 1, 1];
+
+        expect(p1.next.equals(p2), false);
+        expect(p1.previous.equals(p2), false);
+        expect(p1.parent.equals(p2), false);
+
+        p1 = [];
+        p2 = [];
+
+        expect(p1.next.equals(p2), true);
+        expect(p2.previous.equals(p1), true);
+        expect(p1.parent.equals(p2), true);
+
+        p1 = [1, 0, 2];
+        p2 = [1, 0];
+
+        expect(p1.parent.equals(p2), true);
+        expect(p2.parent.equals(p1), false);
+      },
+    );
   });
 }