pact-js VS msw

First, he shows the official pact.io websites. Then, he clicks on the “View on Github” button by selecting Node JS and Javascript from the list of options.

It just just enough abstraction over the basics of converting your HTTP calls to GraphQL queries and mutations, but ALL of the parsing of responses is on you. I’m well versed in parsing JSON in Elm. I’m also familiar with the compiler errors as well as runtime errors you get with JSON that doesn’t match up to what you designed. At some point I’ll probably have to move beyond the unit tests and add contact tests, maybe via Pact.js.

> I also wasn't aware that "unit" referred to an isolated test, not to the SUT.

I'm with you. That claim is unsubstantiated. It seems to trace to the belief that the first unit tests were XUnit family, thus were SUnit for Scheme. But Kent Beck made it pretty clear that SUnit "units" were classes.

https://web.archive.org/web/20150315073817/http://www.xprogr...

There were unit tests before that. SUnit took its name from common parlance, not vice versa. It was a strange naming convention, given that the unit testing framework could be used to test anything and not just units. Much like the slightly older Test Anything Protocol (TAP) could.

> [on unit tests] This does lead to a lot of work maintaining them whenever the implementation changes, but this is a necessary chore because of the value they provide.

I disagree. Unit tests can still be behavioral. Then they change whenever the behavior changes. They should still work with a mere implementation change.

> This is why I still think that the traditional test pyramid is the best model to follow.

I'll disagree a little with that, too. I think a newer test pyramid that uses contract testing to verify integrations is better. The notion of contract tests is much newer than the pyramids and, properly applied, can speed up feedback by orders of magnitude while also cutting debugging time and maintenance by orders of magnitude.

On that front, I love what Pact is doing and would like to see more competition in the area. Hottest thing in testing since Cypress/Playwright . . .

https://pact.io

I've worked in places where Pact [0] was used for testing services developed by different teams (external) and teams themselves (internal)

[0] https://pact.io/

I'd never heard anyone call those "integrity tests" before. I think "contract test" is more common.

Assuming I understood you, that is.

I've been telling everyone to look at Pact to make contract testing easier to organize and maintain and to make it easier to trigger in the other tests in CI when an interface's behavior changes. They haven't offered me a commission yet. ;-)

https://pact.io

We use pact and since introducing it we have significantly increased velocity and reduced test cycles as it catches things very early. For system tests we hand write them using whatever test frameworks the team is used to.

There is also Pact https://pact.io/ for a language agnostic pact testing.

When you wish to focus on the contract ( which kind of field is required, ...), you shoud use contract testing frameworks. As you seem to leverage a microservices, a consumer driven contract testing approach with a framework like Pact.js is recommended.

However, I discovered a great combination that transformed my API call testing in TypeScript: Vitest and Mock Service Worker (MSW). Their well-crafted design makes them incredibly easy to use, enhancing the overall testing experience.

While mocks are effective, they require modifying the component's internal logic or mocking global functions like fetch. This can become cumbersome for complex components with numerous API interactions. Here's where MSW shines.

> For those wondering what the use case is, you must not have tried it. It does take work to set up (with each version that's less), but it can be very nice to test in isolation esp in cases where a component is under a login, the 4th page of a 10 page form, etc. Also obviously if you're working on a component library that ships without an app, Storybook can be your development and/or demo app.

I have worked with storybook extensively over the past couple of years and my team is moving away from it in favour of MSW (https://mswjs.io).

For "4th page of a 10 page form" during the development there's hot reloading which is really stable nowadays and haven't failed me, although I understand that some setups are old and it might be easier to configure Storybook than good hot reloading.

I'm not entirely sure about the testing part of it and I'd be grateful if you could elaborate. I haven't felt the need for some special setup with SB because for unit tests, I can test a deeply nested component separately. For E2E tests, I usually test the whole form.

I agree on the component library part, this is probably the only use case where Storybook is 100% justified, but I'm unconvinced about the

Additionally, thank you to all our community launch partners across the frontend ecosystem for helping us bring Storybook 8 to the world! Thanks to Chromatic, Figma, ViteConf, Omlet, DivRiots, story.to.design, StackBlitz, UXpin, Nx, Mock Service Worker, Anima, Zeplin, zeroheight, kickstartDS, and Kendo UI.

similar with msw.js, but fully automated

they could be network mocks (use msw)

With orval, we can also integrate the API client in our unit tests. Orval provides first class support for mocking through the (Mock Service Worker)[https://mswjs.io/] library, and it can automatically generate the MSW handlers for testing server.

Consider a hypothetical scenario where data from a list of companies within an ERP needs to be retrieved. As a personal recommendation, leverage tools like MSW for top-level mocks, which can significantly enhance the testing process.