fix sandwich recipe detection test

SerialPrograms/Source/PokemonSV/Inference/Picnics/PokemonSV_SandwichRecipeDetector.cpp

@@ -127,6 +127,18 @@ bool SandwichRecipeSelectionWatcher::process_frame(const VideoSnapshot& frame){
     return num_arrows_found == 1;
 }
 
+bool SandwichRecipeSelectionWatcher::detect(const ImageViewRGB32& frame){
+    int num_arrows_found = 0;
+    for(int i = 0; i < 6; i++){
+        const bool found_arrow = m_arrow_watchers[i].detect(frame);
+        if (found_arrow){
+            m_selected_recipe = i;
+            num_arrows_found++;
+        }
+    }
+    return num_arrows_found == 1;
+}
+
 }
 }
 }

SerialPrograms/Source/PokemonSV/Inference/Picnics/PokemonSV_SandwichRecipeDetector.h

@@ -56,6 +56,11 @@ class SandwichRecipeSelectionWatcher : public VisualInferenceCallback{
     virtual void make_overlays(VideoOverlaySet& items) const override;
     virtual bool process_frame(const VideoSnapshot& frame) override;
 
+    // Whether it can detect the recipe selection on this frame.
+    // Unlike `process_frame()` which relies on consecutive frames to give robust result,
+    // this function uses only one frame.
+    bool detect(const ImageViewRGB32& frame);
+
     // Return which recipe cell is currented selected.
     // For cell order, see `SandwichRecipeNumberDetector`.
     // If no cell selection detected, return -1.

SerialPrograms/Source/Tests/PokemonSV_Tests.cpp

@@ -184,7 +184,7 @@ int test_pokemonSV_SandwichRecipeDetector(const ImageViewRGB32& image, const std
         cerr << "Error: word " << words[words.size()-1] << " is wrong. Must be an integer in range [0, 6). " << endl;
     }
     SandwichRecipeSelectionWatcher selection_watcher;
-    bool result = selection_watcher.process_frame({image.copy(), current_time()});
+    bool result = selection_watcher.detect(image);
 
     TEST_RESULT_COMPONENT_EQUAL(result, true, "SandwichRecipeSelectionWatcher::process_frame() result");