attempt to fix cadnano export bug (still not fixed)

test/export_cadnano_v2_test.dart

@@ -297,15 +297,9 @@ main() {
     });
 
     test('test_paranemic_crossover_other_direction', () async {
-      var helices = [
-        Helix(idx: 1, max_offset: 64, grid_position: GridPosition(19, 14), grid: Grid.square),
-        Helix(idx: 0, max_offset: 64, grid_position: GridPosition(19, 15), grid: Grid.square),
-        Helix(idx: 3, max_offset: 64, grid_position: GridPosition(19, 16), grid: Grid.square),
-        Helix(idx: 2, max_offset: 64, grid_position: GridPosition(19, 17), grid: Grid.square),
-      ];
-      var design = Design(helices: helices, grid: Grid.square);
-      design = design.draw_strand(3, 24).to(8).cross(1, 24).to(8).as_scaffold().commit();
-      design = design.draw_strand(2, 50).to(24).cross(0, 50).to(24).commit();
+      String filename = 'test_paranemic_crossover_other_direction.sc';
+      Design design = Design.from_json_str(
+          await get_text_file_content('../test/tests_inputs/cadnano_v2_export/${filename}'))!;
 
       String output_json = to_cadnano_v2_json(design);
       Design output_design = Design.from_cadnano_v2_json_str(output_json);

test/tests_inputs/cadnano_v2_export/test_paranemic_crossover_other_direction.sc

@@ -0,0 +1,27 @@
+{
+  "version": "0.19.4",
+  "grid": "square",
+  "helices": [
+    {"grid_position": [19, 14], "idx": 1, "max_offset": 64},
+    {"grid_position": [19, 15], "idx": 0, "max_offset": 64},
+    {"grid_position": [19, 16], "idx": 3, "max_offset": 64},
+    {"grid_position": [19, 17], "idx": 2, "max_offset": 64}
+  ],
+  "strands": [
+    {
+      "color": "#0066cc",
+      "is_scaffold": true,
+      "domains": [
+        {"helix": 3, "forward": false, "start": 8, "end": 24},
+        {"helix": 1, "forward": false, "start": 8, "end": 24}
+      ]
+    },
+    {
+      "color": "#007200",
+      "domains": [
+        {"helix": 2, "forward": false, "start": 24, "end": 50},
+        {"helix": 0, "forward": false, "start": 24, "end": 50}
+      ]
+    }
+  ]
+}