Description
Mutate supplied valid number, UUID, and IP strings and retain each allowlisted core's success shape, validity flag, and structured issues.
A parser corpus pairs literal input spellings or structured documents with observable parser results or explicitly constructed expectations. Successful parsing, semantic validity, and exact round-trip preservation are separate properties, so test records retain the relevant evidence.
Mutate supplied valid number, UUID, and IP strings and retain each allowlisted core's success shape, validity flag, and structured issues.
When to use this tool
Use this generator to create reproducible structured validation error corpus cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.
How to use the tool and how it works
- Supply originals, count in the field shapes below. Set seed when you need an explicit replay.
- Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
- Read cases. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.
Preflight every supplied original against the selected number, UUID, or IP validator. Sample originals and mutate them by appending an exclamation mark or deleting one UTF-16 position. Retain originalResult and the complete mutated validator result for comparison.1
Delegated operations used for this result: number; uuid. Their calculation or parsing conventions apply to the corresponding result fields.2, 3
| Input field | Meaning and units | Accepted input |
|---|---|---|
| originals | Originals | Required. Array of Object; no unknown keys.; minimum items 1; maximum items 128. |
| originals[].kind | Kind | Required. Text; one of "number", "uuid", "ip". |
| originals[].text | Text | Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 512. |
| count | Requested count; the mechanics explain whether one draw expands into several returned records. | Required. Safe integer; minimum 1; maximum 128. |
| seed | Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed. | Optional. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| cases | Cases | Required. Array of Object; no unknown keys.; minimum items 1; maximum items 128. |
| cases[].kind | Kind | Required. Text; one of "number", "uuid", "ip". |
| cases[].original | Original | Required. Text; maximum UTF-16 length 4096. |
| cases[].originalResult | Original Result | Required. Object; no unknown keys. or Object; no unknown keys. |
| cases[].mutation | Mutation | Required. Text; one of "append", "delete". |
| cases[].position | Position | Required. Safe integer. |
| cases[].text | Text | Required. Text; maximum UTF-16 length 4096. |
| cases[].result | Result | Required. Object; no unknown keys. or Object; no unknown keys. |
| randomness | Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source. | Required. Object; no unknown keys. |
| randomness.seed | Optional numeric replay seed; normalization and precedence are explained below. | Required. Safe integer. or Null. |
| randomness.source | Source | Required. Text; one of "context", "seed". |
An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.
{
"input": {
"originals": [
{
"kind": "number",
"text": "12.5"
},
{
"kind": "uuid",
"text": "550e8400-e29b-41d4-a716-446655440000"
}
],
"count": 1,
"seed": 42
},
"output": {
"cases": [
{
"kind": "uuid",
"original": "550e8400-e29b-41d4-a716-446655440000",
"originalResult": {
"ok": true,
"output": {
"normalized": "550e8400-e29b-41d4-a716-446655440000",
"valid": true,
"version": 4
}
},
"mutation": "append",
"position": 36,
"text": "550e8400-e29b-41d4-a716-446655440000!",
"result": {
"ok": true,
"output": {
"normalized": "",
"valid": false,
"version": 0
}
}
}
],
"randomness": {
"seed": 42,
"source": "seed"
}
}
}Limitations and assumptions
- A mutation can remain valid. A successful call returning valid false differs from a malformed-input error. The finite mutation bank is not comprehensive parser or security coverage.
- A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
- The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.
Alternative or Complementary methods
For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.
References
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