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TS exposes custom transformers through the public API, so it should be possible to create generates purely from a type alias. I've done something like before with babel as Flow.

import { fromType } from 'kitimat-type-to-gen';

const person = fromType<Person>();

// would expand to something like...

const kitimat = require('kitimat-jest');
const person = kitimat.object<Person>({
  name: kitimat.string(),
  age: kitimat.posInt(),
  // ... etc
});

Seems like this would involve allowing a property to accept a runner as an argument. Create a new runner that would complete as soon as a single test case proves the property. In kitimat-jest it would look the same as check

import { integer, exists } from 'kitimat-jest';

exists("a thing", integer(), a => expect(a).toEqual(0));

This function would be the "snapshot testing" of property-based tests - don't want to use much effort and just have something that does a general sanity check that the function won't throw.

import { integer } from 'kitimat-jest';

fuzz('my func doesn\'t throw', [integer()], int => myFunc(int));

Maybe this should also try to throw garbage and see that there is an exception if the wrong type is passed.

We should be able to specify what options are defaults and which can simply be an extension so that we don't have to continuously add options for things that we don't care about, e.g. kitimat-jest is the only thing that cares about the timeout option.

Also, the options.ts module is the only thing that relies on path and cosmiconfig which makes it annoying to use Kitimat directly in the browser. (something I want to do)

Like this talk but probably using Chromeless. For more information, see https://en.wikipedia.org/wiki/Model-based_testing.

Q: is there a tool that transforms .d.ts into .js.flow?

ala https://clojure.org/about/spec, https://clojure.org/guides/spec

Seems more natural for someone to use number instead of integer or float.

import { number } from 'kitimat-jest';

const fuzz = number();

Inspired by mockServer in GraphQL tools, create GraphQL bindings for Kitimat. Given a schema.json and a query, I should create a generator.

import { fromGraphQL } from 'kitimat-graphql';
improt schema from './schema.json';

const server = fromGraphQL(schema);

const queryGen = server(`query {
  me {
    id
    name
  }
}`);

check('my component renders', queryGen, result => {
  // ...
});

I'm already squating kitimat-graphql in packages.

I'd be interested in an integration with the ava test runner, since it's what I use. (I'm open to contributing myself, but I have a lot of other projects. Hopefully it's not too hard, and so I'll give it a try since I know ava stuff 😅)

While experimenting with this library, I found an issue that seemingly makes it very difficult to work with. It could be that I'm doing something wrong, or that there have been changes in jest since this library was last updated.

Demonstration code:
https://github.com/chrismilleruk/testapp/tree/kitimat-jest

Given a simple generative test which fails:

check('Always starts with a letter', 
  [string(), string()], 
  (generatedPrefix, generatedName) => {
  const module = new Greeting(generatedPrefix);
  const result = module.sayHello(generatedName);

  // Always starts with a letter
  expect(result[0]).toMatch(/[A-Za-z]/);
});

The reporter output doesn't provide

• the arguments which caused the failure.
• the seed used to create the arguments.

...
✕ Always starts with a letter (seed: undefined, source: undefined) (26ms)
✓ Has four basic formats (33ms)

● Greeting Class › Always starts with a letter (seed: undefined, source: undefined)

expect(received).toMatch(expected)

Expected pattern: /[A-Za-z]/
Received string:  " "

  37 |
  38 |     // Always starts with a letter
> 39 |     expect(result[0]).toMatch(/[A-Za-z]/);
     |                       ^
  40 |   });
...

Make it possible to use React propTypes to generate props for your component.

import { fromPropTypes } from 'kitimat-prop-types';
jest.mock('prop-types', () => require('kitimat-prop-types/mock'));

import { App } from './app';

const propsGen = fromPropTypes(App);

// ...

Already squating on kitimat-prop-types in packages.