Fix n+1 and write test for new selector

nest/recipes/steps/selectors.py

@@ -21,7 +21,11 @@ def get_step_ingredient_items_for_steps(
 
     step_ingredient_items = RecipeStepIngredientItem.objects.filter(
         step_id__in=step_ids
-    ).select_related("ingredient_item__ingredient__product__unit")
+    ).select_related(
+        "ingredient_item__ingredient_group",
+        "ingredient_item__ingredient__product__unit",
+        "ingredient_item__portion_quantity_unit",
+    )
 
     for step_ingredient_item in step_ingredient_items:
         if step_ingredient_item.ingredient_item is None:

tests/recipes/test_steps_selectors.py

@@ -1,2 +1,53 @@
-def test_selector_get_step_ingredient_items_for_steps():
-    assert False
+import pytest
+
+from nest.recipes.steps.selectors import get_step_ingredient_items_for_steps
+
+
+@pytest.mark.products(
+    product1={"name": "product1"},
+    product2={"name": "product2"},
+    product3={"name": "product3"},
+)
+@pytest.mark.recipe_ingredients(
+    ingredient1={"title": "Ingredient 1", "product": "product1"},
+    ingredient2={"title": "Ingredient 2", "product": "product2"},
+    ingredient3={"title": "Ingredient 3", "product": "product3"},
+)
+@pytest.mark.recipe_ingredient_item_groups(
+    group1={"title": "Group 1"},
+    group2={"title": "Group 2"},
+)
+@pytest.mark.recipe_ingredient_items(
+    item1={"ingredient_group": "group1", "ingredient": "ingredient1"},
+    item2={"ingredient_group": "group1", "ingredient": "ingredient2"},
+    item3={"ingredient_group": "group2", "ingredient": "ingredient3"},
+)
+@pytest.mark.recipe_steps(
+    step1={"number": 1},
+    step2={"number": 2},
+    step3={"number": 3},
+    step4={"number": 4},
+)
+@pytest.mark.recipe_step_ingredient_items(
+    step_item1={"step": "step1", "ingredient_item": "item1"},
+    step_item2={"step": "step1", "ingredient_item": "item2"},
+    step_item3={"step": "step2", "ingredient_item": "item1"},
+    step_item4={"step": "step4", "ingredient_item": "item3"},
+)
+def test_selector_get_step_ingredient_items_for_steps(
+    recipe_steps, recipe_step_ingredient_items, django_assert_num_queries
+):
+    """
+    Test that the get_step_ingredient_items_for_steps selector correctly retrieves
+    result within query limits.
+    """
+    step_ids = [step.id for step in recipe_steps.values()]
+
+    with django_assert_num_queries(1):
+        step_items = get_step_ingredient_items_for_steps(step_ids=step_ids)
+
+    assert len(step_items.keys()) == len(step_ids)
+    assert len(step_items[recipe_steps["step1"].id]) == 2
+    assert len(step_items[recipe_steps["step2"].id]) == 1
+    assert len(step_items[recipe_steps["step3"].id]) == 0
+    assert len(step_items[recipe_steps["step4"].id]) == 1