test: add coverage for Product Bundle Balance report

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

erpnext/stock/report/product_bundle_balance/test_product_bundle_balance.py

@@ -0,0 +1,43 @@
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+
+from erpnext.stock.doctype.item.test_item import make_item
+from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+from erpnext.stock.report.product_bundle_balance.product_bundle_balance import execute
+from erpnext.tests.utils import ERPNextTestSuite
+
+WH = "_Test Warehouse - _TC"
+
+
+class TestProductBundleBalance(ERPNextTestSuite):
+	def make_bundle(self, parent, child_qty):
+		bundle = frappe.get_doc({"doctype": "Product Bundle", "new_item_code": parent})
+		for item_code, qty in child_qty.items():
+			bundle.append("items", {"item_code": item_code, "qty": qty})
+		bundle.insert()
+		bundle.submit()
+
+	def run_report(self, item_code):
+		filters = frappe._dict({"company": "_Test Company", "item_code": item_code})
+		return execute(filters)[1]
+
+	def test_bundle_qty_is_limited_by_scarcest_child(self):
+		parent = make_item(properties={"is_stock_item": 0, "is_sales_item": 1}).name
+		child_a = make_item(properties={"is_stock_item": 1}).name
+		child_b = make_item(properties={"is_stock_item": 1}).name
+		self.make_bundle(parent, {child_a: 2, child_b: 1})
+
+		make_stock_entry(item_code=child_a, to_warehouse=WH, qty=10, rate=100)
+		make_stock_entry(item_code=child_b, to_warehouse=WH, qty=3, rate=100)
+
+		data = self.run_report(parent)
+		parent_row = next(r for r in data if r["item_code"] == parent and r["indent"] == 0)
+		# min(10 // 2, 3 // 1) = min(5, 3) = 3 buildable bundles
+		self.assertEqual(parent_row["bundle_qty"], 3)
+
+		row_a = next(r for r in data if r["item_code"] == child_a and r["indent"] == 1)
+		row_b = next(r for r in data if r["item_code"] == child_b and r["indent"] == 1)
+		self.assertEqual((row_a["actual_qty"], row_a["minimum_qty"], row_a["bundle_qty"]), (10, 2, 5))
+		self.assertEqual((row_b["actual_qty"], row_b["minimum_qty"], row_b["bundle_qty"]), (3, 1, 3))