Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Payroll journal entry: withholding liability · case 01
The payroll entry does not balance; employer taxes have no liability.
Payroll journal entry: withholding liability · case 02
The payroll entry does not balance; employer taxes have no liability.
Payroll journal entry: withholding liability · case 03
The payroll entry does not balance; employer taxes have no liability.
Payroll journal entry: withholding liability · case 04
The payroll entry does not balance; employer taxes have no liability.
Payroll journal entry: withholding liability · case 05
The payroll entry does not balance; employer taxes have no liability.
Payroll journal entry: pre-tax deduction scope · case 01
Income tax is withheld on benefit contributions that are pre-tax.
Payroll journal entry: pre-tax deduction scope · case 02
Income tax is withheld on benefit contributions that are pre-tax.
Payroll journal entry: pre-tax deduction scope · case 03
Income tax is withheld on benefit contributions that are pre-tax.
Payroll journal entry: pre-tax deduction scope · case 04
Income tax is withheld on benefit contributions that are pre-tax.
Payroll journal entry: pre-tax deduction scope · case 05
Income tax is withheld on benefit contributions that are pre-tax.
Straight-line depreciation journal: first charge month · case 01
Mid-month assets start depreciating a month late.
Straight-line depreciation journal: first charge month · case 02
Mid-month assets start depreciating a month late.
Straight-line depreciation journal: first charge month · case 03
Mid-month assets start depreciating a month late.
Straight-line depreciation journal: first charge month · case 04
Mid-month assets start depreciating a month late.
Straight-line depreciation journal: first charge month · case 05
Mid-month assets start depreciating a month late.
Straight-line depreciation journal: mid-month half steps · case 01
Mid-month assets take twice the useful life to depreciate.
Straight-line depreciation journal: mid-month half steps · case 02
Mid-month assets take twice the useful life to depreciate.
Straight-line depreciation journal: mid-month half steps · case 03
Mid-month assets take twice the useful life to depreciate.
Straight-line depreciation journal: mid-month half steps · case 04
Mid-month assets take twice the useful life to depreciate.
Straight-line depreciation journal: mid-month half steps · case 05
Mid-month assets take twice the useful life to depreciate.
Straight-line depreciation journal: accumulated cap · case 01
Mid-month assets depreciate below salvage value in the final month.
Straight-line depreciation journal: accumulated cap · case 02
Mid-month assets depreciate below salvage value in the final month.
Straight-line depreciation journal: accumulated cap · case 03
Mid-month assets depreciate below salvage value in the final month.
Straight-line depreciation journal: accumulated cap · case 04
Mid-month assets depreciate below salvage value in the final month.
Straight-line depreciation journal: accumulated cap · case 05
Mid-month assets depreciate below salvage value in the final month.
Straight-line depreciation journal: salvage exclusion · case 01
Monthly charges are too high for assets with salvage value.
Straight-line depreciation journal: salvage exclusion · case 02
Monthly charges are too high for assets with salvage value.
Straight-line depreciation journal: salvage exclusion · case 03
Monthly charges are too high for assets with salvage value.
Straight-line depreciation journal: salvage exclusion · case 04
Monthly charges are too high for assets with salvage value.
Straight-line depreciation journal: salvage exclusion · case 05
Monthly charges are too high for assets with salvage value.
Straight-line depreciation journal: cumulative rounding · case 01
The last months of a schedule carry large rounding catch-up amounts.
Straight-line depreciation journal: cumulative rounding · case 02
The last months of a schedule carry large rounding catch-up amounts.
Straight-line depreciation journal: cumulative rounding · case 03
The last months of a schedule carry large rounding catch-up amounts.
Straight-line depreciation journal: cumulative rounding · case 04
The last months of a schedule carry large rounding catch-up amounts.
Straight-line depreciation journal: cumulative rounding · case 05
The last months of a schedule carry large rounding catch-up amounts.
Straight-line depreciation journal: through month inclusivity · case 01
The depreciation run omits the charge for the month it is run through.
Straight-line depreciation journal: through month inclusivity · case 02
The depreciation run omits the charge for the month it is run through.
Straight-line depreciation journal: through month inclusivity · case 03
The depreciation run omits the charge for the month it is run through.
Straight-line depreciation journal: through month inclusivity · case 04
The depreciation run omits the charge for the month it is run through.
Straight-line depreciation journal: through month inclusivity · case 05
The depreciation run omits the charge for the month it is run through.
Level payment with final adjustment: monthly periodic rate · case 01
Quoted payments are roughly twelve times the interest a borrower actually owes.
Level payment with final adjustment: monthly periodic rate · case 02
Quoted payments are roughly twelve times the interest a borrower actually owes.
Level payment with final adjustment: monthly periodic rate · case 03
Quoted payments are roughly twelve times the interest a borrower actually owes.
Level payment with final adjustment: monthly periodic rate · case 04
Quoted payments are roughly twelve times the interest a borrower actually owes.
Level payment with final adjustment: monthly periodic rate · case 05
Quoted payments are roughly twelve times the interest a borrower actually owes.
Level payment with final adjustment: annuity discount exponent · case 01
The level payment is too large and the final payment turns out smaller than the rest.
Level payment with final adjustment: annuity discount exponent · case 02
The level payment is too large and the final payment turns out smaller than the rest.
Level payment with final adjustment: annuity discount exponent · case 03
The level payment is too large and the final payment turns out smaller than the rest.
Level payment with final adjustment: annuity discount exponent · case 04
The level payment is too large and the final payment turns out smaller than the rest.
Level payment with final adjustment: annuity discount exponent · case 05
The level payment is too large and the final payment turns out smaller than the rest.
Level payment with final adjustment: zero-rate payment · case 01
Interest-free loans leave a large catch-up final payment when rounding up.
Level payment with final adjustment: zero-rate payment · case 02
Interest-free loans leave a large catch-up final payment when rounding up.
Level payment with final adjustment: zero-rate payment · case 03
Interest-free loans leave a large catch-up final payment when rounding up.
Level payment with final adjustment: zero-rate payment · case 04
Interest-free loans leave a large catch-up final payment when rounding up.
Level payment with final adjustment: zero-rate payment · case 05
Interest-free loans leave a large catch-up final payment when rounding up.
Level payment with final adjustment: round-up mode · case 01
Loans configured to round the payment up get a payment rounded down.
Level payment with final adjustment: round-up mode · case 02
Loans configured to round the payment up get a payment rounded down.
Level payment with final adjustment: round-up mode · case 03
Loans configured to round the payment up get a payment rounded down.
Level payment with final adjustment: round-up mode · case 04
Loans configured to round the payment up get a payment rounded down.
Level payment with final adjustment: round-up mode · case 05
Loans configured to round the payment up get a payment rounded down.
Level payment with final adjustment: nearest tie rule · case 01
An exact half-cent payment is rounded down on even cents.
Level payment with final adjustment: nearest tie rule · case 02
An exact half-cent payment is rounded down on even cents.
Level payment with final adjustment: nearest tie rule · case 03
An exact half-cent payment is rounded down on even cents.
Level payment with final adjustment: nearest tie rule · case 04
An exact half-cent payment is rounded down on even cents.
Level payment with final adjustment: nearest tie rule · case 05
An exact half-cent payment is rounded down on even cents.
Level payment with final adjustment: monthly interest rounding · case 01
Total interest is a few cents low across the schedule.
Level payment with final adjustment: monthly interest rounding · case 02
Total interest is a few cents low across the schedule.
Level payment with final adjustment: monthly interest rounding · case 03
Total interest is a few cents low across the schedule.
Level payment with final adjustment: monthly interest rounding · case 04
Total interest is a few cents low across the schedule.
Level payment with final adjustment: monthly interest rounding · case 05
Total interest is a few cents low across the schedule.
Level payment with final adjustment: final payment amount · case 01
The last payment ignores the rounding residue left in the balance.
Level payment with final adjustment: final payment amount · case 02
The last payment ignores the rounding residue left in the balance.
Level payment with final adjustment: final payment amount · case 03
The last payment ignores the rounding residue left in the balance.
Level payment with final adjustment: final payment amount · case 04
The last payment ignores the rounding residue left in the balance.
Level payment with final adjustment: final payment amount · case 05
The last payment ignores the rounding residue left in the balance.
Schedule rows from a fixed payment: interest-only guard · case 01
A payment that exactly equals interest produces rows that never reduce principal.
Schedule rows from a fixed payment: interest-only guard · case 02
A payment that exactly equals interest produces rows that never reduce principal.
Schedule rows from a fixed payment: interest-only guard · case 03
A payment that exactly equals interest produces rows that never reduce principal.
Schedule rows from a fixed payment: interest-only guard · case 04
A payment that exactly equals interest produces rows that never reduce principal.
Schedule rows from a fixed payment: interest-only guard · case 05
A payment that exactly equals interest produces rows that never reduce principal.
Schedule rows from a fixed payment: final principal clamp · case 01
The last schedule row drives the balance negative.
Schedule rows from a fixed payment: final principal clamp · case 02
The last schedule row drives the balance negative.
Schedule rows from a fixed payment: final principal clamp · case 03
The last schedule row drives the balance negative.
Schedule rows from a fixed payment: final principal clamp · case 04
The last schedule row drives the balance negative.
Schedule rows from a fixed payment: final principal clamp · case 05
The last schedule row drives the balance negative.
Schedule rows from a fixed payment: paid-off stop · case 01
Paid-off loans keep producing zero rows until max_months.
Schedule rows from a fixed payment: paid-off stop · case 02
Paid-off loans keep producing zero rows until max_months.
Schedule rows from a fixed payment: paid-off stop · case 03
Paid-off loans keep producing zero rows until max_months.
Schedule rows from a fixed payment: paid-off stop · case 04
Paid-off loans keep producing zero rows until max_months.
Schedule rows from a fixed payment: paid-off stop · case 05
Paid-off loans keep producing zero rows until max_months.
Schedule rows from a fixed payment: interest base · case 01
Interest stays flat every month even as principal is repaid.
Schedule rows from a fixed payment: interest base · case 02
Interest stays flat every month even as principal is repaid.
Schedule rows from a fixed payment: interest base · case 03
Interest stays flat every month even as principal is repaid.
Schedule rows from a fixed payment: interest base · case 04
Interest stays flat every month even as principal is repaid.
Schedule rows from a fixed payment: interest base · case 05
Interest stays flat every month even as principal is repaid.
Schedule rows from a fixed payment: balloon amount · case 01
The reported balloon includes another month of interest.
Schedule rows from a fixed payment: balloon amount · case 02
The reported balloon includes another month of interest.
Schedule rows from a fixed payment: balloon amount · case 03
The reported balloon includes another month of interest.
Schedule rows from a fixed payment: balloon amount · case 04
The reported balloon includes another month of interest.
Schedule rows from a fixed payment: balloon amount · case 05
The reported balloon includes another month of interest.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗