unit consistency changes

tests/test_quantity_consistency.py

@@ -0,0 +1,196 @@
+import pytest
+
+from app.database import (
+    calculate_meal_nutrition,
+    Food,
+    Meal,
+    MealFood,
+)
+
+
+def test_meal_nutrition_uses_grams_correctly(db_session):
+    """Verify that MealFood.quantity as grams calculates nutrition correctly"""
+    # Create a food: 100 cal per 100g
+    food = Food(
+        name="Test Food",
+        serving_size=100.0,
+        serving_unit="g",
+        calories=100.0,
+        protein=10.0,
+        carbs=20.0,
+        fat=5.0
+    )
+    db_session.add(food)
+    db_session.commit()
+    
+    # Create a meal with 200g of this food
+    meal = Meal(name="Test Meal", meal_type="breakfast")
+    db_session.add(meal)
+    db_session.commit()
+    
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=food.id,
+        quantity=200.0  # 200 grams
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+    
+    # Calculate nutrition
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    
+    # Should be 2x the base values (200g / 100g = 2x multiplier)
+    assert nutrition['calories'] == 200.0
+    assert nutrition['protein'] == 20.0
+    assert nutrition['carbs'] == 40.0
+    assert nutrition['fat'] == 10.0
+
+
+def test_fractional_servings(db_session):
+    """Test that fractional grams work correctly"""
+    food = Food(
+        name="Test Food",
+        serving_size=100.0,
+        serving_unit="g",
+        calories=100.0
+    )
+    db_session.add(food)
+    db_session.commit()
+    
+    meal = Meal(name="Test Meal")
+    db_session.add(meal)
+    db_session.commit()
+    
+    # Add 50g (half serving)
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=food.id,
+        quantity=50.0
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+    
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    assert nutrition['calories'] == 50.0
+
+
+def test_zero_serving_size_handling(db_session):
+    """Test handling of zero serving_size - should not divide by zero"""
+    food = Food(
+        name="Test Food Zero Serving",
+        serving_size=0.0,
+        serving_unit="g",
+        calories=100.0
+    )
+    db_session.add(food)
+    db_session.commit()
+    
+    meal = Meal(name="Test Meal Zero")
+    db_session.add(meal)
+    db_session.commit()
+    
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=food.id,
+        quantity=100.0
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+    
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    # Multiplier should be 0, so no nutrition added
+    assert nutrition['calories'] == 0.0
+
+
+def test_small_gram_values(db_session):
+    """Test very small gram values (e.g., 0.1g)"""
+    food = Food(
+        name="Test Food Small",
+        serving_size=100.0,
+        serving_unit="g",
+        calories=100.0
+    )
+    db_session.add(food)
+    db_session.commit()
+    
+    meal = Meal(name="Test Meal Small")
+    db_session.add(meal)
+    db_session.commit()
+    
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=food.id,
+        quantity=0.1  # Very small amount
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+    
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    # Should be 0.001x multiplier
+    assert nutrition['calories'] == 0.1
+
+
+def test_large_gram_values(db_session):
+    """Test large gram values (e.g., 10000g)"""
+    food = Food(
+        name="Test Food Large",
+        serving_size=100.0,
+        serving_unit="g",
+        calories=100.0
+    )
+    db_session.add(food)
+    db_session.commit()
+    
+    meal = Meal(name="Test Meal Large")
+    db_session.add(meal)
+    db_session.commit()
+    
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=food.id,
+        quantity=10000.0  # Very large amount
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+    
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    # Should be 100x multiplier
+    assert nutrition['calories'] == 10000.0
+
+
+def test_invalid_serving_size(db_session):
+    """Test invalid/non-numeric serving_size values"""
+    # First create a valid food to test with
+    valid_food = Food(
+        name="Test Food Valid",
+        serving_size=100.0,
+        serving_unit="g",
+        calories=100.0
+    )
+    db_session.add(valid_food)
+    db_session.commit()
+
+    # Now create a meal and add the valid food
+    meal = Meal(name="Test Meal Valid")
+    db_session.add(meal)
+    db_session.commit()
+
+    meal_food = MealFood(
+        meal_id=meal.id,
+        food_id=valid_food.id,
+        quantity=100.0
+    )
+    db_session.add(meal_food)
+    db_session.commit()
+
+    # Test that the calculation works with valid serving_size
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    assert nutrition['calories'] == 100.0
+
+    # Now test with None serving_size by updating the food
+    valid_food.serving_size = None
+    db_session.commit()
+
+    # Recalculate - should handle None gracefully
+    nutrition = calculate_meal_nutrition(meal, db_session)
+    assert nutrition['calories'] == 0