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
Five-or-nine digit postal code: space-separated plus-four is rejected · case 01
"12029 4101" returns None although a space separator is allowed.
Five-or-nine digit postal code: space-separated plus-four is rejected · case 02
"12029 4101" returns None although a space separator is allowed.
Five-or-nine digit postal code: space-separated plus-four is rejected · case 03
"12029 4101" returns None although a space separator is allowed.
Five-or-nine digit postal code: space-separated plus-four is rejected · case 04
"12029 4101" returns None although a space separator is allowed.
Five-or-nine digit postal code: space-separated plus-four is rejected · case 05
"12029 4101" returns None although a space separator is allowed.
Five-or-nine digit postal code: placeholder plus-four is kept · case 01
"12029-0000" is returned with its placeholder extension instead of "12029".
Five-or-nine digit postal code: placeholder plus-four is kept · case 02
"12029-0000" is returned with its placeholder extension instead of "12029".
Five-or-nine digit postal code: placeholder plus-four is kept · case 03
"12029-0000" is returned with its placeholder extension instead of "12029".
Five-or-nine digit postal code: placeholder plus-four is kept · case 04
"12029-0000" is returned with its placeholder extension instead of "12029".
Five-or-nine digit postal code: placeholder plus-four is kept · case 05
"12029-0000" is returned with its placeholder extension instead of "12029".
Five-or-nine digit postal code: partial codes are truncated into valid ones · case 01
A seven-digit string is cut to its first five digits and accepted.
Five-or-nine digit postal code: partial codes are truncated into valid ones · case 02
A seven-digit string is cut to its first five digits and accepted.
Five-or-nine digit postal code: partial codes are truncated into valid ones · case 03
A seven-digit string is cut to its first five digits and accepted.
Five-or-nine digit postal code: partial codes are truncated into valid ones · case 04
A seven-digit string is cut to its first five digits and accepted.
Five-or-nine digit postal code: partial codes are truncated into valid ones · case 05
A seven-digit string is cut to its first five digits and accepted.
Five-or-nine digit postal code: letters pass as code digits · case 01
"1203O" with a letter O is returned as a valid code.
Five-or-nine digit postal code: letters pass as code digits · case 02
"1203O" with a letter O is returned as a valid code.
Five-or-nine digit postal code: letters pass as code digits · case 03
"1203O" with a letter O is returned as a valid code.
Five-or-nine digit postal code: letters pass as code digits · case 04
"1203O" with a letter O is returned as a valid code.
Five-or-nine digit postal code: letters pass as code digits · case 05
"1203O" with a letter O is returned as a valid code.
Five-or-nine digit postal code: form padding makes valid codes fail · case 01
" 12029" with a leading space from a form field is rejected.
Five-or-nine digit postal code: form padding makes valid codes fail · case 02
" 12029" with a leading space from a form field is rejected.
Five-or-nine digit postal code: form padding makes valid codes fail · case 03
" 12029" with a leading space from a form field is rejected.
Five-or-nine digit postal code: form padding makes valid codes fail · case 04
" 12029" with a leading space from a form field is rejected.
Five-or-nine digit postal code: form padding makes valid codes fail · case 05
" 12029" with a leading space from a form field is rejected.
Outward-inward postcode formatter: the typed space is kept inside the code · case 01
"ZX3 9ZZ" is rejected because the outward part ends in a space.
Outward-inward postcode formatter: the typed space is kept inside the code · case 02
"ZX3 9ZZ" is rejected because the outward part ends in a space.
Outward-inward postcode formatter: the typed space is kept inside the code · case 03
"ZX3 9ZZ" is rejected because the outward part ends in a space.
Outward-inward postcode formatter: the typed space is kept inside the code · case 04
"ZX3 9ZZ" is rejected because the outward part ends in a space.
Outward-inward postcode formatter: the typed space is kept inside the code · case 05
"ZX3 9ZZ" is rejected because the outward part ends in a space.
Outward-inward postcode formatter: case is never normalized · case 01
Lowercase codes come back lowercase and lowercase forbidden letters pass validation.
Outward-inward postcode formatter: case is never normalized · case 02
Lowercase codes come back lowercase and lowercase forbidden letters pass validation.
Outward-inward postcode formatter: case is never normalized · case 03
Lowercase codes come back lowercase and lowercase forbidden letters pass validation.
Outward-inward postcode formatter: case is never normalized · case 04
Lowercase codes come back lowercase and lowercase forbidden letters pass validation.
Outward-inward postcode formatter: case is never normalized · case 05
Lowercase codes come back lowercase and lowercase forbidden letters pass validation.
Outward-inward postcode formatter: the code is split at its midpoint · case 01
Seven-character codes with a four-character outward part are rejected.
Outward-inward postcode formatter: the code is split at its midpoint · case 02
Seven-character codes with a four-character outward part are rejected.
Outward-inward postcode formatter: the code is split at its midpoint · case 03
Seven-character codes with a four-character outward part are rejected.
Outward-inward postcode formatter: the code is split at its midpoint · case 04
Seven-character codes with a four-character outward part are rejected.
Outward-inward postcode formatter: the code is split at its midpoint · case 05
Seven-character codes with a four-character outward part are rejected.
Outward-inward postcode formatter: inward pattern accepts a digit in letter position · case 01
"ZX3 99Z" is accepted.
Outward-inward postcode formatter: inward pattern accepts a digit in letter position · case 02
"ZX3 99Z" is accepted.
Outward-inward postcode formatter: inward pattern accepts a digit in letter position · case 03
"ZX3 99Z" is accepted.
Outward-inward postcode formatter: inward pattern accepts a digit in letter position · case 04
"ZX3 99Z" is accepted.
Outward-inward postcode formatter: inward pattern accepts a digit in letter position · case 05
"ZX3 99Z" is accepted.
Outward-inward postcode formatter: forbidden letters checked in the wrong positions · case 01
"ZX3 9AV" passes because only the first inward letter is tested.
Outward-inward postcode formatter: forbidden letters checked in the wrong positions · case 02
"ZX3 9AV" passes because only the first inward letter is tested.
Outward-inward postcode formatter: forbidden letters checked in the wrong positions · case 03
"ZX3 9AV" passes because only the first inward letter is tested.
Outward-inward postcode formatter: forbidden letters checked in the wrong positions · case 04
"ZX3 9AV" passes because only the first inward letter is tested.
Outward-inward postcode formatter: forbidden letters checked in the wrong positions · case 05
"ZX3 9AV" passes because only the first inward letter is tested.
Outward-inward postcode formatter: eight-character codes are accepted · case 01
"ZX3AB9ZZ" becomes "ZX3AB 9ZZ".
Outward-inward postcode formatter: eight-character codes are accepted · case 02
"ZX3AB9ZZ" becomes "ZX3AB 9ZZ".
Outward-inward postcode formatter: eight-character codes are accepted · case 03
"ZX3AB9ZZ" becomes "ZX3AB 9ZZ".
Outward-inward postcode formatter: eight-character codes are accepted · case 04
"ZX3AB9ZZ" becomes "ZX3AB 9ZZ".
Outward-inward postcode formatter: eight-character codes are accepted · case 05
"ZX3AB9ZZ" becomes "ZX3AB 9ZZ".
Outward-inward postcode formatter: letter-only outward codes are accepted · case 01
"ZXY 9ZZ" is formatted as valid.
Outward-inward postcode formatter: letter-only outward codes are accepted · case 02
"ZXY 9ZZ" is formatted as valid.
Outward-inward postcode formatter: letter-only outward codes are accepted · case 03
"ZXY 9ZZ" is formatted as valid.
Outward-inward postcode formatter: letter-only outward codes are accepted · case 04
"ZXY 9ZZ" is formatted as valid.
Outward-inward postcode formatter: letter-only outward codes are accepted · case 05
"ZXY 9ZZ" is formatted as valid.
Alternating letter-digit postal code: a hyphen separator is accepted · case 01
"K1A-4B1" normalizes to "K1A 4B1" although only a space separator is allowed.
Alternating letter-digit postal code: a hyphen separator is accepted · case 02
"K1A-4B1" normalizes to "K1A 4B1" although only a space separator is allowed.
Alternating letter-digit postal code: a hyphen separator is accepted · case 03
"K1A-4B1" normalizes to "K1A 4B1" although only a space separator is allowed.
Alternating letter-digit postal code: a hyphen separator is accepted · case 04
"K1A-4B1" normalizes to "K1A 4B1" although only a space separator is allowed.
Alternating letter-digit postal code: a hyphen separator is accepted · case 05
"K1A-4B1" normalizes to "K1A 4B1" although only a space separator is allowed.
Alternating letter-digit postal code: letter and digit positions are swapped · case 01
Every valid code is rejected.
Alternating letter-digit postal code: letter and digit positions are swapped · case 02
Every valid code is rejected.
Alternating letter-digit postal code: letter and digit positions are swapped · case 03
Every valid code is rejected.
Alternating letter-digit postal code: letter and digit positions are swapped · case 04
Every valid code is rejected.
Alternating letter-digit postal code: letter and digit positions are swapped · case 05
Every valid code is rejected.
Alternating letter-digit postal code: forbidden letters are checked only at the first position · case 01
"K1U 4B1" is accepted although U is forbidden everywhere.
Alternating letter-digit postal code: forbidden letters are checked only at the first position · case 02
"K1U 4B1" is accepted although U is forbidden everywhere.
Alternating letter-digit postal code: forbidden letters are checked only at the first position · case 03
"K1U 4B1" is accepted although U is forbidden everywhere.
Alternating letter-digit postal code: forbidden letters are checked only at the first position · case 04
"K1U 4B1" is accepted although U is forbidden everywhere.
Alternating letter-digit postal code: forbidden letters are checked only at the first position · case 05
"K1U 4B1" is accepted although U is forbidden everywhere.
Alternating letter-digit postal code: a leading Z is accepted · case 01
"Z1A 4B1" is accepted.
Alternating letter-digit postal code: a leading Z is accepted · case 02
"Z1A 4B1" is accepted.
Alternating letter-digit postal code: a leading Z is accepted · case 03
"Z1A 4B1" is accepted.
Alternating letter-digit postal code: a leading Z is accepted · case 04
"Z1A 4B1" is accepted.
Alternating letter-digit postal code: a leading Z is accepted · case 05
"Z1A 4B1" is accepted.
Alternating letter-digit postal code: the canonical space is not reinserted · case 01
Codes are returned compact, so spaced and compact input normalize the same only by accident.
Alternating letter-digit postal code: the canonical space is not reinserted · case 02
Codes are returned compact, so spaced and compact input normalize the same only by accident.
Alternating letter-digit postal code: the canonical space is not reinserted · case 03
Codes are returned compact, so spaced and compact input normalize the same only by accident.
Alternating letter-digit postal code: the canonical space is not reinserted · case 04
Codes are returned compact, so spaced and compact input normalize the same only by accident.
Alternating letter-digit postal code: the canonical space is not reinserted · case 05
Codes are returned compact, so spaced and compact input normalize the same only by accident.
Alternating letter-digit postal code: overlong codes pass the length test · case 01
"K1A4B1C" is returned as "K1A 4B1C".
Alternating letter-digit postal code: overlong codes pass the length test · case 02
"K1A4B1C" is returned as "K1A 4B1C".
Alternating letter-digit postal code: overlong codes pass the length test · case 03
"K1A4B1C" is returned as "K1A 4B1C".
Alternating letter-digit postal code: overlong codes pass the length test · case 04
"K1A4B1C" is returned as "K1A 4B1C".
Alternating letter-digit postal code: overlong codes pass the length test · case 05
"K1A4B1C" is returned as "K1A 4B1C".
Address label line wrapper: the joining space is not counted · case 01
A line one character longer than the label width is produced.
Address label line wrapper: the joining space is not counted · case 02
A line one character longer than the label width is produced.
Address label line wrapper: the joining space is not counted · case 03
A line one character longer than the label width is produced.
Address label line wrapper: the joining space is not counted · case 04
A line one character longer than the label width is produced.
Address label line wrapper: the joining space is not counted · case 05
A line one character longer than the label width is produced.
Address label line wrapper: a label that exactly fills the budget is flagged · case 01
Two lines with a two-line budget report overflow.
Address label line wrapper: a label that exactly fills the budget is flagged · case 02
Two lines with a two-line budget report overflow.
Address label line wrapper: a label that exactly fills the budget is flagged · case 03
Two lines with a two-line budget report overflow.
Address label line wrapper: a label that exactly fills the budget is flagged · case 04
Two lines with a two-line budget report overflow.
Address label line wrapper: a label that exactly fills the budget is flagged · case 05
Two lines with a two-line budget report overflow.
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 ↗