Improve coverage for mutation addConfigurableProductToCart

[TomashKhamlai]

testAddOutOfStockProduct()
not covered all possible scenarios

Preconditions (*)

Steps to reproduce (*)

1. Create Configurable Product with
   Name Configurable Product
   SKU: configurable-product
   Weight: 1
   Price: 1
   Variations:

• sku: configurable-product-option1, qty: 1000, price: 10
• sku: configurable-product-option2, qty: 1000, price: 10

2. Create empty cart as a Guest or as Customer (GraphQL)
3. Add configurable product to Cart (GraphQL)
4. Go to admin
5. Set Configurable product to be Out of Stock but don't change anything in configurable variations
6. Add configurable product to Cart again (GraphQL)

mutation {
  addConfigurableProductsToCart(
    input: {
      cart_id: "{{ CART_ID }}"
      cartItems: [
        {
          variant_sku: "useless-field"
          data: {
            qty: 11
            sku: "configurable-product-option1"
          }
        }
        {
          variant_sku: "useless-field"
          data: {
            qty: 11
            sku: "configurable-product-option2"
          }
        }
      ]
    }
  ) {
    cart {
      items {
        qty
      }
    }
  }
}

Expected result (*)

1. When we try to add the product to the cart
   

2. When we try to proceed to checkout
   

Actual result (*)

1. Product is added to cart

{
  "data": {
    "addConfigurableProductsToCart": {
      "cart": {
        "items": [
          {
            "qty": 5034
          },
          {
            "qty": 5034
          }
        ]
      }
    }
  }
}

[rogyar]

I would recommend postponing testing virtual products until the mutation is fixed. Currently, adding virtual products to cart does not work. Current routine does not take into account variant_sku and adds only simple products to the shopping cart.
It's also related to #349

In a few words, we need to achieve the following scenario:

• Specify configurable product(s) for adding to cart
• Specify super attributes (configurable options) for the configurable product
• Add the configurable product to the shopping cart
• Check the database, quote_item table contains a configurable product and a simple product that corresponds the selected super attributes. The simple products have configurable cart item ID in the parent_item_id field.

I have ideas about the fix but need to discuss with @naydav.

[rogyar]

@TomashKhamlai I described the problem in details here #438

[TomashKhamlai]

Ok, I understood what you explain. #439 describes the problem and expectations that could be in future in a more simple manner.

[naydav]

Closed due to work on
#438