perf: Add load test for large quantity adds and updates

packages/dev-server/load-testing/graphql/shop/adjust-order-line.graphql

@@ -0,0 +1,12 @@
+mutation ($id: ID! $qty: Int!) {
+    adjustOrderLine(orderLineId: $id quantity: $qty) {
+        ...on Order {
+            id
+            code
+            totalQuantity
+        }
+        ...on ErrorResult {
+            errorCode
+        }
+    }
+}

packages/dev-server/load-testing/scripts/very-large-order3.js

@@ -0,0 +1,49 @@
+// @ts-check
+import { check } from 'k6';
+import { ShopApiRequest } from '../utils/api-request.js';
+
+const searchQuery = new ShopApiRequest('shop/search.graphql');
+const addItemToOrderMutation = new ShopApiRequest('shop/add-to-order.graphql');
+const adjustOrderLineMutation = new ShopApiRequest('shop/adjust-order-line.graphql');
+
+export let options = {
+    stages: [{ duration: '1m', target: 1 }],
+};
+
+export function setup() {
+    const searchResult = searchQuery.post();
+    const items = searchResult.data.search.items;
+    return items;
+}
+
+/**
+ * Continuously adds random items to a single order for the duration of the test.
+ * Just like very-large-order.js but adds 999 items each time, and runs for only 1 minute.
+ * Both addItemToOrder and adjustOrderLine are tested as the latter needs the first and tends to be more complex/slower.
+ */
+export default function (products) {
+    const orderLineId = addToCart(randomItem(products).productVariantId, 999);
+    adjustOrderLine(orderLineId, 1);
+    adjustOrderLine(orderLineId, 999);
+    adjustOrderLine(orderLineId, 0);
+}
+
+function addToCart(variantId, qty) {
+    const result = addItemToOrderMutation.post({ id: variantId, qty });
+    check(result.data, {
+        'Product added to cart': r =>
+            !!r.addItemToOrder.lines.find(l => l.productVariant.id === variantId && l.quantity === qty),
+    });
+    return result.data.addItemToOrder.lines.find(l => l.productVariant.id === variantId).id;
+}
+
+function adjustOrderLine(orderLineId, qty) {
+    const result = adjustOrderLineMutation.post({ id: orderLineId, qty });
+    check(result.data, {
+        'Product quantity adjusted': r => r.adjustOrderLine.totalQuantity === qty,
+    });
+}
+
+function randomItem(items) {
+    return items[Math.floor(Math.random() * items.length)];
+}