feat: Create virtual class for mock testing

src/app/asm/script.h

@@ -23,17 +23,21 @@ namespace snes_asm {
 const std::string kMosaicChangeOffset = "$02AADB";
 constexpr int kSNESToPCOffset = 0x138000;
 
-class Script {
+class ScriptTemplate {
+ public:
+  virtual absl::Status ApplyPatchToROM(ROM& rom) = 0;
+};
+
+class Script : public ScriptTemplate {
  public:
   Script() { asar_init_with_dll_path("assets/libasar.dll"); }
 
+  absl::Status ApplyPatchToROM(ROM& rom) override;
   absl::Status GenerateMosaicChangeAssembly(
       ROM& rom, char mosaic_tiles[core::kNumOverworldMaps], int routine_offset,
       int hook_offset = 0);
 
  private:
-  absl::Status ApplyPatchToROM(ROM& rom);
-
   int64_t patch_size_;
   std::string patch_filename_;
   std::string patch_contents_;