milestone3.js

milestone3.js

// @flow

type Environment = {
  +left: ?number,
  +right: ?number,
}

type AssertionValues = {
  +result: ?number,
}

describe(
  'Min',
  Suite.Function(
    (_: Specimen) => ({
      [_(it)]: (environment: Environment) => require('./Min'),

      ...({left, right}: Environment, {result}: AssertionValues) => ({
        result: Min => expect(Min(left, right)).toEqual(result),
        error: Min => expect(() => Min(left, right)).toThrow(),
      }),
    }),

    (_: Experiment) =>
      _.with(
        {
          left: 4,
        },
        _ => _.and({right: 6}).produces({result: 4}),
        _ => _.and({right: 3}).produces({result: 3}),
        _ => _.and({right: 'asd'}).produces('error'),
      ),

    (_: Experiment) =>
      _.taking('left').from([null, undefined, 'foo'], _ =>
        _.and('right')
          .sample(3) // .sample takes the first 3 numbers from iterable
          .example() // example takes one random element from the sample every time
          .from(Suite.Integers)
          .produces('error'),
      ),
  ),
);