diff --git a/erpnext/stock/report/fifo_queue_vs_qty_after_transaction_comparison/test_fifo_queue_vs_qty_after_transaction_comparison.py b/erpnext/stock/report/fifo_queue_vs_qty_after_transaction_comparison/test_fifo_queue_vs_qty_after_transaction_comparison.py
new file mode 100644
index 00000000000..f930edad2df
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+++ b/erpnext/stock/report/fifo_queue_vs_qty_after_transaction_comparison/test_fifo_queue_vs_qty_after_transaction_comparison.py
@@ -0,0 +1,56 @@
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+
+from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+from erpnext.stock.report.fifo_queue_vs_qty_after_transaction_comparison.fifo_queue_vs_qty_after_transaction_comparison import (
+	execute,
+)
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestFifoQueueVsQtyAfterTransactionComparison(ERPNextTestSuite):
+	def run_report(self, filters: dict) -> list:
+		return execute(frappe._dict(filters))[1]
+
+	def test_healthy_fifo_item_no_mismatch(self):
+		item = "_Test Item"
+		warehouse = "Stores - _TC"
+		frappe.db.set_value("Item", item, "valuation_method", "FIFO")
+
+		make_stock_entry(item_code=item, to_warehouse=warehouse, qty=10, rate=100, posting_date="2026-06-01")
+		make_stock_entry(item_code=item, to_warehouse=warehouse, qty=5, rate=120, posting_date="2026-06-01")
+		make_stock_entry(item_code=item, from_warehouse=warehouse, qty=4, posting_date="2026-06-02")
+
+		data = self.run_report({"company": "_Test Company", "item_code": item, "warehouse": warehouse})
+
+		item_codes = [row.get("item_code") for row in data if row]
+		self.assertNotIn(item, item_codes)
+
+	def test_queue_out_of_sync_is_flagged(self):
+		item = "_Test Item 2"
+		warehouse = "Stores - _TC"
+		frappe.db.set_value("Item", item, "valuation_method", "FIFO")
+
+		entry = make_stock_entry(
+			item_code=item, to_warehouse=warehouse, qty=10, rate=100, posting_date="2026-06-01"
+		)
+		sle = frappe.db.get_value(
+			"Stock Ledger Entry",
+			{"voucher_no": entry.name, "item_code": item, "warehouse": warehouse},
+			"name",
+		)
+
+		# corrupt the running balance so it no longer matches the FIFO queue (the queue holds 10,
+		# but the stored qty_after_transaction now claims 7)
+		frappe.db.set_value("Stock Ledger Entry", sle, "qty_after_transaction", 7, update_modified=False)
+
+		data = self.run_report({"company": "_Test Company", "item_code": item, "warehouse": warehouse})
+
+		flagged = {row.get("name") for row in data if row}
+		self.assertIn(sle, flagged)
+
+	def test_requires_a_filter(self):
+		with self.assertRaises(frappe.ValidationError):
+			self.run_report({"company": "_Test Company"})