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
Overtime regular rate with bonuses and differentials: shift differential in regular rate · case 01
Night-shift workers with overtime are underpaid on their premium.
Overtime regular rate with bonuses and differentials: shift differential in regular rate · case 02
Night-shift workers with overtime are underpaid on their premium.
Overtime regular rate with bonuses and differentials: shift differential in regular rate · case 03
Night-shift workers with overtime are underpaid on their premium.
Overtime regular rate with bonuses and differentials: shift differential in regular rate · case 04
Night-shift workers with overtime are underpaid on their premium.
Overtime regular rate with bonuses and differentials: shift differential in regular rate · case 05
Night-shift workers with overtime are underpaid on their premium.
Overtime regular rate with bonuses and differentials: premium cent rounding · case 01
Overtime premiums ending in a half cent or more are a cent short.
Overtime regular rate with bonuses and differentials: premium cent rounding · case 02
Overtime premiums ending in a half cent or more are a cent short.
Overtime regular rate with bonuses and differentials: premium cent rounding · case 03
Overtime premiums ending in a half cent or more are a cent short.
Overtime regular rate with bonuses and differentials: premium cent rounding · case 04
Overtime premiums ending in a half cent or more are a cent short.
Overtime regular rate with bonuses and differentials: premium cent rounding · case 05
Overtime premiums ending in a half cent or more are a cent short.
Resident and work-state withholding reciprocity: reciprocity pair normalization · case 01
Some reciprocity agreements are ignored depending on which state is the residence.
Resident and work-state withholding reciprocity: reciprocity pair normalization · case 02
Some reciprocity agreements are ignored depending on which state is the residence.
Resident and work-state withholding reciprocity: reciprocity pair normalization · case 03
Some reciprocity agreements are ignored depending on which state is the residence.
Resident and work-state withholding reciprocity: reciprocity pair normalization · case 04
Some reciprocity agreements are ignored depending on which state is the residence.
Resident and work-state withholding reciprocity: reciprocity pair normalization · case 05
Some reciprocity agreements are ignored depending on which state is the residence.
Resident and work-state withholding reciprocity: reciprocal withholding state · case 01
Commuters covered by reciprocity have tax sent to the work state instead of their home state.
Resident and work-state withholding reciprocity: reciprocal withholding state · case 02
Commuters covered by reciprocity have tax sent to the work state instead of their home state.
Resident and work-state withholding reciprocity: reciprocal withholding state · case 03
Commuters covered by reciprocity have tax sent to the work state instead of their home state.
Resident and work-state withholding reciprocity: reciprocal withholding state · case 04
Commuters covered by reciprocity have tax sent to the work state instead of their home state.
Resident and work-state withholding reciprocity: reciprocal withholding state · case 05
Commuters covered by reciprocity have tax sent to the work state instead of their home state.
Resident and work-state withholding reciprocity: resident credit floor · case 01
Employees living in a lower-tax state get a negative resident withholding line.
Resident and work-state withholding reciprocity: resident credit floor · case 02
Employees living in a lower-tax state get a negative resident withholding line.
Resident and work-state withholding reciprocity: resident credit floor · case 03
Employees living in a lower-tax state get a negative resident withholding line.
Resident and work-state withholding reciprocity: resident credit floor · case 04
Employees living in a lower-tax state get a negative resident withholding line.
Resident and work-state withholding reciprocity: resident credit floor · case 05
Employees living in a lower-tax state get a negative resident withholding line.
Resident and work-state withholding reciprocity: zero resident line suppression · case 01
Pay stubs show a zero-cent resident state withholding line.
Resident and work-state withholding reciprocity: zero resident line suppression · case 02
Pay stubs show a zero-cent resident state withholding line.
Resident and work-state withholding reciprocity: zero resident line suppression · case 03
Pay stubs show a zero-cent resident state withholding line.
Resident and work-state withholding reciprocity: zero resident line suppression · case 04
Pay stubs show a zero-cent resident state withholding line.
Resident and work-state withholding reciprocity: zero resident line suppression · case 05
Pay stubs show a zero-cent resident state withholding line.
Resident and work-state withholding reciprocity: credit election · case 01
Resident states without a credit election receive the reduced amount, and vice versa.
Resident and work-state withholding reciprocity: credit election · case 02
Resident states without a credit election receive the reduced amount, and vice versa.
Resident and work-state withholding reciprocity: credit election · case 03
Resident states without a credit election receive the reduced amount, and vice versa.
Resident and work-state withholding reciprocity: credit election · case 04
Resident states without a credit election receive the reduced amount, and vice versa.
Resident and work-state withholding reciprocity: credit election · case 05
Resident states without a credit election receive the reduced amount, and vice versa.
401(k) deferral limit with catch-up: catch-up age test · case 01
Employees turning 50 this year are blocked from catch-up contributions.
401(k) deferral limit with catch-up: catch-up age test · case 02
Employees turning 50 this year are blocked from catch-up contributions.
401(k) deferral limit with catch-up: catch-up age test · case 03
Employees turning 50 this year are blocked from catch-up contributions.
401(k) deferral limit with catch-up: catch-up age test · case 04
Employees turning 50 this year are blocked from catch-up contributions.
401(k) deferral limit with catch-up: catch-up age test · case 05
Employees turning 50 this year are blocked from catch-up contributions.
401(k) deferral limit with catch-up: deferral percentage base · case 01
Deferrals are smaller than the election because they are computed on net pay.
401(k) deferral limit with catch-up: deferral percentage base · case 02
Deferrals are smaller than the election because they are computed on net pay.
401(k) deferral limit with catch-up: deferral percentage base · case 03
Deferrals are smaller than the election because they are computed on net pay.
401(k) deferral limit with catch-up: deferral percentage base · case 04
Deferrals are smaller than the election because they are computed on net pay.
401(k) deferral limit with catch-up: deferral percentage base · case 05
Deferrals are smaller than the election because they are computed on net pay.
401(k) deferral limit with catch-up: available pay limit · case 01
Paychecks with large taxes defer more than the cash available, driving net pay negative.
401(k) deferral limit with catch-up: available pay limit · case 02
Paychecks with large taxes defer more than the cash available, driving net pay negative.
401(k) deferral limit with catch-up: available pay limit · case 03
Paychecks with large taxes defer more than the cash available, driving net pay negative.
401(k) deferral limit with catch-up: available pay limit · case 04
Paychecks with large taxes defer more than the cash available, driving net pay negative.
401(k) deferral limit with catch-up: available pay limit · case 05
Paychecks with large taxes defer more than the cash available, driving net pay negative.
401(k) deferral limit with catch-up: remaining room report · case 01
Reported remaining deferral room ignores year-to-date contributions.
401(k) deferral limit with catch-up: remaining room report · case 02
Reported remaining deferral room ignores year-to-date contributions.
401(k) deferral limit with catch-up: remaining room report · case 03
Reported remaining deferral room ignores year-to-date contributions.
401(k) deferral limit with catch-up: remaining room report · case 04
Reported remaining deferral room ignores year-to-date contributions.
401(k) deferral limit with catch-up: remaining room report · case 05
Reported remaining deferral room ignores year-to-date contributions.
HSA payroll contribution limit by coverage month: last-month rule trigger · case 01
Employees who enroll mid-year are limited to a partial-year amount despite December coverage.
HSA payroll contribution limit by coverage month: last-month rule trigger · case 02
Employees who enroll mid-year are limited to a partial-year amount despite December coverage.
HSA payroll contribution limit by coverage month: last-month rule trigger · case 03
Employees who enroll mid-year are limited to a partial-year amount despite December coverage.
HSA payroll contribution limit by coverage month: last-month rule trigger · case 04
Employees who enroll mid-year are limited to a partial-year amount despite December coverage.
HSA payroll contribution limit by coverage month: last-month rule trigger · case 05
Employees who enroll mid-year are limited to a partial-year amount despite December coverage.
HSA payroll contribution limit by coverage month: employer contributions count · case 01
Employees whose employer also funds the HSA are allowed to exceed the combined limit.
HSA payroll contribution limit by coverage month: employer contributions count · case 02
Employees whose employer also funds the HSA are allowed to exceed the combined limit.
HSA payroll contribution limit by coverage month: employer contributions count · case 03
Employees whose employer also funds the HSA are allowed to exceed the combined limit.
HSA payroll contribution limit by coverage month: employer contributions count · case 04
Employees whose employer also funds the HSA are allowed to exceed the combined limit.
HSA payroll contribution limit by coverage month: employer contributions count · case 05
Employees whose employer also funds the HSA are allowed to exceed the combined limit.
HSA payroll contribution limit by coverage month: catch-up proration · case 01
Part-year participants aged 55 or older receive the full catch-up amount.
HSA payroll contribution limit by coverage month: catch-up proration · case 02
Part-year participants aged 55 or older receive the full catch-up amount.
HSA payroll contribution limit by coverage month: catch-up proration · case 03
Part-year participants aged 55 or older receive the full catch-up amount.
HSA payroll contribution limit by coverage month: catch-up proration · case 04
Part-year participants aged 55 or older receive the full catch-up amount.
HSA payroll contribution limit by coverage month: catch-up proration · case 05
Part-year participants aged 55 or older receive the full catch-up amount.
HSA payroll contribution limit by coverage month: monthly tier summation · case 01
Employees who switched from self to family coverage get the family limit for every covered month.
HSA payroll contribution limit by coverage month: monthly tier summation · case 02
Employees who switched from self to family coverage get the family limit for every covered month.
HSA payroll contribution limit by coverage month: monthly tier summation · case 03
Employees who switched from self to family coverage get the family limit for every covered month.
HSA payroll contribution limit by coverage month: monthly tier summation · case 04
Employees who switched from self to family coverage get the family limit for every covered month.
HSA payroll contribution limit by coverage month: monthly tier summation · case 05
Employees who switched from self to family coverage get the family limit for every covered month.
FUTA liability with credit-reduction states: credit reduction wage base · case 01
Employers in credit-reduction states owe additional FUTA on wages above the 7,000 base.
FUTA liability with credit-reduction states: credit reduction wage base · case 02
Employers in credit-reduction states owe additional FUTA on wages above the 7,000 base.
FUTA liability with credit-reduction states: credit reduction wage base · case 03
Employers in credit-reduction states owe additional FUTA on wages above the 7,000 base.
FUTA liability with credit-reduction states: credit reduction wage base · case 04
Employers in credit-reduction states owe additional FUTA on wages above the 7,000 base.
FUTA liability with credit-reduction states: credit reduction wage base · case 05
Employers in credit-reduction states owe additional FUTA on wages above the 7,000 base.
FUTA liability with credit-reduction states: liability rounding stage · case 01
Quarterly FUTA liability differs by a few cents from the rate applied to total taxable wages.
FUTA liability with credit-reduction states: liability rounding stage · case 02
Quarterly FUTA liability differs by a few cents from the rate applied to total taxable wages.
FUTA liability with credit-reduction states: liability rounding stage · case 03
Quarterly FUTA liability differs by a few cents from the rate applied to total taxable wages.
FUTA liability with credit-reduction states: liability rounding stage · case 04
Quarterly FUTA liability differs by a few cents from the rate applied to total taxable wages.
FUTA liability with credit-reduction states: liability rounding stage · case 05
Quarterly FUTA liability differs by a few cents from the rate applied to total taxable wages.
FUTA liability with credit-reduction states: deposit threshold · case 01
A deposit is demanded when accumulated liability is exactly 500.00.
FUTA liability with credit-reduction states: deposit threshold · case 02
A deposit is demanded when accumulated liability is exactly 500.00.
FUTA liability with credit-reduction states: deposit threshold · case 03
A deposit is demanded when accumulated liability is exactly 500.00.
FUTA liability with credit-reduction states: deposit threshold · case 04
A deposit is demanded when accumulated liability is exactly 500.00.
FUTA liability with credit-reduction states: deposit threshold · case 05
A deposit is demanded when accumulated liability is exactly 500.00.
Net-pay deduction priority and arrears: priority ordering · case 01
Low-priority voluntary deductions consume net pay before mandatory ones.
Net-pay deduction priority and arrears: priority ordering · case 02
Low-priority voluntary deductions consume net pay before mandatory ones.
Net-pay deduction priority and arrears: priority ordering · case 03
Low-priority voluntary deductions consume net pay before mandatory ones.
Net-pay deduction priority and arrears: priority ordering · case 04
Low-priority voluntary deductions consume net pay before mandatory ones.
Net-pay deduction priority and arrears: priority ordering · case 05
Low-priority voluntary deductions consume net pay before mandatory ones.
Net-pay deduction priority and arrears: arrears carried into due amount · case 01
Previously missed deductions are never recovered.
Net-pay deduction priority and arrears: arrears carried into due amount · case 02
Previously missed deductions are never recovered.
Net-pay deduction priority and arrears: arrears carried into due amount · case 03
Previously missed deductions are never recovered.
Net-pay deduction priority and arrears: arrears carried into due amount · case 04
Previously missed deductions are never recovered.
Net-pay deduction priority and arrears: arrears carried into due amount · case 05
Previously missed deductions are never recovered.
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 ↗