https://github.com/meeshkan/json-schema-fast-check

json-schema + fast-check = Property testing in JS with JSON Schema
https://github.com/meeshkan/json-schema-fast-check

Last synced: 3 months ago
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json-schema + fast-check = Property testing in JS with JSON Schema

• Host: GitHub
• URL: https://github.com/meeshkan/json-schema-fast-check
• Owner: meeshkan
• License: mit
• Archived: true
• Created: 2019-08-28T13:30:47.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2022-02-12T13:02:17.000Z (over 2 years ago)
• Last Synced: 2024-05-18T20:33:13.281Z (6 months ago)
• Language: TypeScript
• Homepage:
• Size: 479 KB
• Stars: 20
• Watchers: 3
• Forks: 4
• Open Issues: 10
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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# json-schema-fast-check

[JSON Schema](https://json-schema.org) is a useful way to define input and output schemas.

Property testing is a useful way to make sure that a function behaves as expected with *any* valid input.

`json-schema-fast-check` implements arbitrary JSON Schema values using the [`fast-check`](https://github.com/dubzzz/fast-check) library for property testing.

## Example

```typescript

import jsfc from "json-schema-fast-check";

import fc from "fast-check";

const getAge = (data: any) =>

    typeof data === "object" && typeof data.age === "number"

    ? Math.floor(data.age)

    : null;

const userSchema = {

    type: "object",

    properties: {

        required: ["name", "id"],

        name: {

            type: "string"

        },

        age: {

            type: "integer",

            minimum: 0

        },

        id: {

            type: "integer"

        }

    }

}

test("my function yields positive age or null", () => {

    fc.assert(fc.property(jsfc(userSchema), user => {

        const age = getAge(user);

        return age === null || age >= 0;

    }));

});

```

## API

The API has only two functions - the default one (which we call `jsfc` just cuz) and a helper function called `generate`.

### `jsfc` (default)

```typescript

const arbitrary = jsfc(mySchema);

```

Creates a [`fast-check` arbitrary](https://github.com/dubzzz/fast-check/blob/master/documentation/1-Guides/Arbitraries.md) from valid JSON schema.

### `generate`

```typescript

const json = generate(mySchema);

```

Generates a single valid JSON object that conforms to the schema.

## A note on JSON Schema

The actual schema used here is not JSON Schema but rather a subset of JSON Schema called "The Subest of JSON Schema I Was Not Too Lazy To Define." I also added some `faker-js` sugar (see the tests).

## Contributing

Thanks for wanting to contribute! We will soon have a contributing page detaling how to contribute. Meanwhile, there are plenty of features that haven't been implemented yet. Please check out our [open issues](https://github.com/meeshkan/json-schema-fast-check/issues). We'd really appreciate your help!

Please note that this project is governed by the [Meeshkan Community Code of Conduct](https://github.com/meeshkan/code-of-conduct). By participating in this project, you agree to abide by its terms.