Add Jest helper and support #290
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This is all very cool. I'd just like to point out that none of this is exclusively applicable to Jest. It should apply to any BDD testing system that exposes an |
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@jayandcatchfire If you are interested, I can give you collaborator privileges over at my fork and we can work on this together to get it approved by maintainers of this repo. |
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An invite has been sent :) I'm happy to generalize this for any BDD frameworks like you have suggested, but I'll need some guidance here. |
| * @param testFn function that expects, in proper jest syntax | ||
| * @param opts options for jsverify | ||
| */ | ||
| function itHolds(description, arbitrary, testFn, options) { |
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My reworked version supports everything that jsc.property supports since it just wraps that.
| ```js | ||
| describe("a simple jest test suite", function () { | ||
| itHolds("(b && b) === b", jsc.bool, function (b) { | ||
| expect(b && b).toBe(b); |
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I don't understand, isn't it's simpler to write
describe("a simple jest test suite", function () {
itHolds("(b && b) === b", jsc.bool, function (b) {
expect(b && b).toBe(b);
return true; // if you forget this your test will fail, so it's not a silent error
});
});Does jest support asynchronous tests (returning promise or calling callback), how these work?
Can't itHolds be implemented using jsc.property?
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@jayandcatchfire maybe you can answer this?
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Jest does support asynchronous tests by means of passing an asynchronous function to it. I'm not sure how/if that would work with jsverify. I'll have to dig a little bit.
As for using jsc.property, that's not how I originally wrote my helper, but I'll play with it and see if that would work. Keep in mind I was using typescript, so I wasn't concerned about using the DSL.
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Thanks for helping out on this @jayandcatchfire
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Okay, I played a bit with jsc.property. The reason I originally avoided it was because I found the documentation a bit ambiguous. Now that I've read its source and played with it, it appears that the only important difference between my helper and jsc.property is that mine returns true at the end so the test doesn't fail even when nothing throws in the test function.
I just rewrote my function as the following and it appears to work in all the existing cases I've tried.
function itHolds(...args: any[]) {
const initial = args.slice(0, -1);
const prop = args[args.length - 1];
jsc.property(...initial, (...args: any[]) => {
prop(...args);
return true;
});
}Of course, this was quick and dirty. I haven't accounted for any of the types here, which is bad form.
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Here's my final version that retains proper typing:
import * as jsc from 'jsverify';
/* tslint:disable:max-line-length */
export function itHolds<A>(description: String, arb1: jsc.Arbitrary<A>, prop: (t: A) => jsc.Property<A>): any;
export function itHolds<A, B>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, prop: (t: A, u: B) => jsc.Property<any>): any;
export function itHolds<A, B, C>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, prop: (t: A, u: B, v: C) => jsc.Property<any>): any;
export function itHolds<A, B, C, D>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, prop: (t: A, u: B, v: C, w: D) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, prop: (t: A, u: B, v: C, w: D, e: E) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E, F>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, arb6: jsc.Arbitrary<F>, prop: (t: A, u: B, v: C, w: D, e: E, a: F) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E, F, G>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, arb6: jsc.Arbitrary<F>, arb7: jsc.Arbitrary<G>, prop: (t: A, u: B, v: C, w: D, e: E, a: F, b: G) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E, F, G, H>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, arb6: jsc.Arbitrary<F>, arb7: jsc.Arbitrary<G>, arb8: jsc.Arbitrary<H>, prop: (t: A, u: B, v: C, w: D, e: E, a: F, b: G, c: H) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E, F, G, H, I>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, arb6: jsc.Arbitrary<F>, arb7: jsc.Arbitrary<G>, arb8: jsc.Arbitrary<H>, arb9: jsc.Arbitrary<I>, prop: (t: A, u: B, v: C, w: D, e: E, a: F, b: G, c: H, d: I) => jsc.Property<any>): any;
export function itHolds<A, B, C, D, E, F, G, H, I, J>(description: String, arb1: jsc.Arbitrary<A>, arb2: jsc.Arbitrary<B>, arb3: jsc.Arbitrary<C>, arb4: jsc.Arbitrary<D>, arb5: jsc.Arbitrary<E>, arb6: jsc.Arbitrary<F>, arb7: jsc.Arbitrary<G>, arb8: jsc.Arbitrary<H>, arb9: jsc.Arbitrary<I>, arb10: jsc.Arbitrary<J>, prop: (t: A, u: B, v: C, w: D, e: E, a: F, b: G, c: H, d: I, f: J) => jsc.Property<any>): any;
/* tslint:enable:max-line-length */
/**
* wrapper function for using jsverify with BDD syntax
*/
export function itHolds(...args: any[]): any {
const initial = args.slice(0, -1);
const prop = args[args.length - 1];
jsc.property(...initial, (...args: any[]): boolean => {
prop(...args);
return true;
});
}I still don't know if/how this would support async tests.
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Just fyi @jayandcatchfire, you have access to push direct changes to this PR. |
I'm not sure of the best way to apply my changes for two reasons.
@phadej, can you weigh in on how you'd prefer this to work? |
This PR fixes #289 and fixes #281.
In this PR, I've taken a first stab at adding support for Jest. The reasons for this is discussed in #289. This PR is heavily inspired by @jayandcatchfire and the work shown in #281.
So far, I have done the following:
I have run
make testandmake literate, and both commands yield the expected results.However, I'm not sure how users will be requiring the helper and I'm not sure how to push the helper into the build pipeline. It would be good to get some guidance on this, perhaps @phadej can provide some guidance?
Thanks for your time :)