k6-expect

k6 library that simplifies writing tests in functional way by providing a simple and jest-like syntax for expectations.

Usage

Get started

export default function () {
    describe("Check", t => {
        const r = http.get("https://jsonplaceholder.typicode.com/users/10");
        
        // specialized and type-safe assertions 
        // ... for k6 http response 
        t.expect(response(r, x => x.ok(), x => x.validJson()))
        // ... for primitives
          .and("Id", num(r.json("id"), x => x.toEqual(10)))
          .and("Name", str(r.json("name"), x => x.not().toBeEmpty()))
          .and("Phone number", str(r.json("phone"), x => x.regex("\\d{3}-\\d{3}-\\d{4}")))
          .and("Geolocation", num(r.json("address.geo.lat"), x => x.lessThan(0)))
          .and("Company", str(r.json("company.name"), x => x.toContain("LLC")));
    });
}

Output:

     █ User check
       ✓ https://jsonplaceholder.typicode.com/users/10 is 200
       ✓ https://jsonplaceholder.typicode.com/users/10 responded with valid json
       ✓ Id is 10
       ✓ Name is not empty
       ✓ Phone number matches '\d{3}-\d{3}-\d{4}' pattern
       ✓ Geolocation is less than 0
       ✓ Company contains 'LLC'

For more information, check this examples.

Pass custom context

export class FooContext implements TestSuiteContext {
  breakOnFirstAssert: boolean;
  
  constructor() {
    this.breakOnFirstAssert = true;
  }

  sanitizeUrl(url: string): string {
    return "";
  }

  customFunction() { /* custom logic */ }
}

let fooContext = new FooContext();

export default function () {
    describe("Check", t => {
        // Test logic
        // ...
        // Access to custom logic
        t.context!.customFunction();
    }, fooContext);
}

Typescript integration

Based on k6-template-typescript.

package.json:

{
  "devDependencies": {
    "k6-expect": "X.X.X"
  }
}

webpack.config.js:

// ...
module.exports = {
  // ...
    externals: [
        function ({context, request}, c) {
            if (request.startsWith('k6') || request.startsWith('https://')) {
                return request === 'k6-expect' ? c() : c(null, 'commonjs ' + request);
            }
            return c();
        },
    ],
  // ...
}

Assertions table

Access Function	Assertion	Supports negation	Description
that()	nil	✓	Check value for `null` or `undefined`
	null	✓	Check value for `null`
	toEqual	✓	Check value for equality
bool()	toBeTruthy	✗	Check value for truth
	toBeFalsy	✗	Check value for falsity
collection()	toBeEmpty	✓	Check array for emptiness
	length	✓	Check array for length
	toContain	✓	Check array for occurence of an item
num()	zero	✓	Check value for zero
	between	✓	Check value for a hit in the interval (inclusive)
	greaterThan	✓	Check that value is greater
	greaterThanOrEqual	✓	Check that value is greater or equal
	lessThan	✓	Check that value is less
	lessThanOrEqual	✓	Check that value is less or equal
str()	toBeEmpty	✓	Check value for emptiness
	regex	✓	Check that value matches the pattern
	toContain	✓	Check value for occurence of a string
response()	validJson	✓	Check that response contains valid json
	success	✓	Check that response has successful status (200-299)
	status	✓	Check that response has status specified
	ok	✓	Check response for `200 OK`
	accepted	✓	Check response for `202 ACCEPTED`
	noContent	✓	Check response for `204 NO CONTENT`
	badRequest	✓	Check response for `400 BAD REQUEST`
	unauthorized	✓	Check response for `401 UNAUTHORIZED`
	forbidden	✓	Check response for `403 FORBIDDEN`
	notFound	✓	Check response for `404 NOT FOUND`
	length	✓	Check response body length

LICENSE

Distributed under the MIT License. See LICENSE for more information.