Random File Upload Progress Fixture Generator

Description

Construct synthetic queued/uploading/failed/retry/cancel/complete traces with per-file monotonic integer percentages and immutable snapshots, without file or network access.

An interface fixture makes content and state explicit so a consumer can test a rendering or interaction. Literal labels, modeled states, and calculated geometry remain separate from what a browser or assistive technology actually displays or announces.

Construct synthetic queued/uploading/failed/retry/cancel/complete traces with per-file monotonic integer percentages and immutable snapshots, without file or network access.

When to use this tool

Use this generator to create reproducible file upload progress fixture 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 fileNames, eventCount, maximumIncrement 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 initial, events, final. Use the conventions below. Keep answer-bearing fields separate when presenting an exercise.

Maintain queued, uploading, failed, complete, or canceled file states. Sample starts, failures, cancellations, retries, and positive capped progress advances, recording a full state snapshot after each event.^[1]

Input field	Meaning and units	Accepted input
fileNames	File Names	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 128.; minimum items 1; maximum items 16.
eventCount	Event Count	Required. Safe integer; minimum 1; maximum 32.
maximumIncrement	Maximum Increment	Required. Safe integer; minimum 1; maximum 100.
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
initial	Initial	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 16.
initial[].id	Literal identifier used independently of display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 32.
initial[].name	Name	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
initial[].status	Named outcome; interpret associated null fields and error evidence under the stated convention.	Required. Text; one of "queued", "uploading", "failed", "canceled", "complete".
initial[].progress	Progress	Required. Safe integer; minimum 0; maximum 100.
events	Events	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
events[].fileId	File Id	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 32.
events[].action	Action	Required. Text; one of "start", "advance", "fail", "retry", "cancel", "terminal".
events[].before	Before	Required. Safe integer; minimum 0; maximum 100.
events[].after	After	Required. Safe integer; minimum 0; maximum 100.
events[].files	Files	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 16.
events[].files[].id	Literal identifier used independently of display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 32.
events[].files[].name	Name	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
events[].files[].status	Named outcome; interpret associated null fields and error evidence under the stated convention.	Required. Text; one of "queued", "uploading", "failed", "canceled", "complete".
events[].files[].progress	Progress	Required. Safe integer; minimum 0; maximum 100.
final	Final	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 16.
final[].id	Literal identifier used independently of display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 32.
final[].name	Name	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 128.
final[].status	Named outcome; interpret associated null fields and error evidence under the stated convention.	Required. Text; one of "queued", "uploading", "failed", "canceled", "complete".
final[].progress	Progress	Required. Safe integer; minimum 0; maximum 100.
randomness	Replay source and normalized 32-bit seed, or null seed for an advancing context source.	Required. Object; no unknown keys.
randomness.seed	Optional safe-integer 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.

json

{
  "input": {
    "fileNames": [
      "report.pdf"
    ],
    "eventCount": 3,
    "maximumIncrement": 50,
    "seed": 42
  },
  "output": {
    "initial": [
      {
        "id": "upload-0",
        "name": "report.pdf",
        "status": "queued",
        "progress": 0
      }
    ],
    "events": [
      {
        "fileId": "upload-0",
        "action": "start",
        "before": 0,
        "after": 0,
        "files": [
          {
            "id": "upload-0",
            "name": "report.pdf",
            "status": "uploading",
            "progress": 0
          }
        ]
      },
      {
        "fileId": "upload-0",
        "action": "advance",
        "before": 0,
        "after": 34,
        "files": [
          {
            "id": "upload-0",
            "name": "report.pdf",
            "status": "uploading",
            "progress": 34
          }
        ]
      },
      {
        "fileId": "upload-0",
        "action": "cancel",
        "before": 34,
        "after": 34,
        "files": [
          {
            "id": "upload-0",
            "name": "report.pdf",
            "status": "canceled",
            "progress": 34
          }
        ]
      }
    ],
    "final": [
      {
        "id": "upload-0",
        "name": "report.pdf",
        "status": "canceled",
        "progress": 34
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Retry resumes retained progress rather than resetting it. Complete and canceled files stay terminal. Names are preview text and no file is read, transferred, stored, or uploaded.
A replay requires the same complete input and implementation. The stated sampling convention applies within its eligible space. A finite draw does not exhaust all possible outputs; repeats remain possible unless a distinct-selection rule is explicit.
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

Tool behavior and example: Random File Upload Progress Fixture Generator — tool.io

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