test: add stock to avoid NegativeStockError (#24941)

diff --git a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
index 1b95578..90e2144 100644
--- a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
@@ -1800,6 +1800,15 @@
 		si.selling_price_list = "_Test Price List Rest of the World"
 		si.update_stock = 1
 		si.items[0].target_warehouse = 'Work In Progress - TCP1'
+
+		# Add stock to stores for succesful stock transfer
+		make_stock_entry(
+			target="Stores - TCP1",
+			company = "_Test Company with perpetual inventory",
+			qty=1,
+			basic_rate=100
+		)
+
 		add_taxes(si)
 		si.save()
 
@@ -2269,4 +2278,4 @@
 		"cost_center": "Main - TCP1",
 		"description": "Excise Duty",
 		"rate": 12
-	})
\ No newline at end of file
+	})