Comparison of low-level spying and mocking capabilities between SignOn and Jest
Differences in asynchronous testing methodologies
Contrasting stubs and mocks in Cypress and Jest
Analysis of network-level spying with Cypress Intercept and MSW
Developer experience and observability in testing
Testing is a crucial aspect of software development, ensuring that applications run as expected and are free of bugs. The choice of testing tools can significantly influence the efficiency and effectiveness of the testing process. In this exploration, we delve into the capabilities of SignOn, Jest, Cypress, and the React Testing Library (RTL), highlighting their strengths and weaknesses.
At the core of low-level testing are spying and mocking capabilities. SignOn and Jest offer similar APIs for spy functions, which are essential for monitoring function calls. Both tools allow for the verification of whether functions have been called and provide alternatives for achieving this. However, SignOn excels with its custom matchers, making it easier for developers to use straightforward APIs. In contrast, Jest requires more manual work to create custom matchers, which may be why they are less frequently utilized.
Asynchronous testing presents its own set of challenges. Both SignOn and Jest offer solutions, but they differ in execution. SignOn provides a more fluid approach by wrapping promises and making direct assertions, while Jest requires developers to gather promises and utilize Promise.all to verify their order. This difference can make asynchronous testing feel more intuitive on the SignOn side.
When it comes to stubs and mocks, Cypress and Jest take different approaches. CyStub and JestFn serve similar purposes, allowing developers to stub object methods. However, the distinction between mock implementations and mock return values can be confusing in Jest. Cypress provides clearer abstractions, making it easier to ensure that specific methods return expected values. This clarity can be particularly beneficial when working with complex promises.
Network-level spying and mocking capabilities are essential for comprehensive testing. Cypress Intercept and Mock Service Worker (MSW) are two tools that enable this functionality. While MSW offers a paradigm shift by allowing network-level mocking away from the source code, it requires more setup and lacks the flexibility of Cypress Intercept. Cypress excels with its simpler API, enabling developers to write less code and maintain flexibility by defining or altering handlers within test blocks.
The developer experience is a significant factor in choosing a testing tool. Cypress offers full observability, providing a real browser environment that mirrors a full application. This environment allows developers to see exactly what happens with the component, network, and DOM. In contrast, RTL is more limited, offering only HTML in the terminal, which can leave developers in the dark when diagnosing issues.
Testing tools like Cypress, Jest, and RTL each have their strengths. Cypress stands out for its declarative convenience, offering less code and a better developer experience, especially for complex components. Jest and RTL provide imperative possibilities but require more effort to achieve the same results. Understanding these differences can help developers choose the right tools for their testing needs, balancing ease of use with comprehensive testing capabilities.
CCT vs RTL talks about the similarities between the tools, the differences, compares the ways of doing the same things with the tools, and finally gives a developer experience comparison demo.
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Cypress offers a superior developer experience by leveraging a real browser environment that allows inspection and debugging directly through DevTools, providing immediate feedback and detailed insights into component behavior. React Testing Moibrary, while effective for testing, relies on terminal outputs that may not provide as much detail or immediate feedback.
Cypress Intercept provides a simpler and more flexible API for managing network requests, allowing changes in intercepts directly within test blocks. Mock Service Worker, while robust, requires more setup and lacks the ability to modify handlers within individual tests, making Cypress more suitable for dynamic test scenarios.
Cypress Component Testing provides a real browser environment with full access to DevTools and network activities, enhancing observability and debugging capabilities. React Testing Library, on the other hand, operates within the terminal using HTML outputs, which may limit direct interaction with component states and behaviors.
Cypress Component Testing allows you to mount components in a manner similar to how they are mounted in your application, using custom mounts to simplify complexities, thus enabling a more realistic testing environment.
Both Cypress and Jest offer spying and mocking capabilities, but they differ in implementation. Cypress uses a more declarative approach with simple syntax, while Jest requires more setup and often a more detailed, imperative approach to achieve similar outcomes.
The Talk discusses the differences between Cypress component testing and React Testing Library (RTL). It highlights the benefits of using Cypress Component Testing, such as easier handling of complex components and a more stable testing experience in CI. The comparison between SignOn and Jest focuses on low-level spying and mocking capabilities. The comparison between Cypress Intercept and Mock Service Worker (MSW) examines their network spy and mocking capabilities. The Talk also emphasizes the superior developer experience and observability provided by Cypress component testing compared to RTL.
1. Cypress Component Testing vs React Testing Library
Hello, everyone. My name is Murat, and today I'll be talking about Cypress component testing versus React Testing Library. We've been using Cypress Component Testing at X10, my company, for one year, and we've been doing end-to-end tests for two years. In React, you may run into the situation where you have to wrap your component with many providers. This is a Cypress Component Test for a simple component from the book. Here's the second example, it's a text field, we're typing into it, it can also be read-only. On the left, Cypress, when we're mounting the component, we use site.stop instead and alias. Here is the third component, you're clicking on each one and ensuring that we're in a certain route and we want to make sure that the thing we click on is highlighted and the things we don't click on are not highlighted. The more complex the component gets, the more benefit you will have from the Cypress API and you will have a little less code accomplishing the same thing. But the real seller is the HTML versus browser.
2. Cypress Component Tests vs RTL Examples
So in Cypress, we can easily get the window object and call the get current position method with a fake position object. However, in RTL, we need to do some extra work to achieve the same result.
3. Comparing SignOn and Jest
Let's compare the low-level spying and mocking capabilities of SignOn and Jest. They have similar APIs, but SignOn provides some convenient custom matchers. Asynchronous testing is slightly different between the two, but the end result is the same. When it comes to stubs and mocks, CyStub is comparable to JestFn, but the implementation and usage differ. Cynon provides nice abstractions for dealing with promises, but Jest requires more effort. Working with Jest in the React community has built expertise and a vested interest.
4. Comparing Cypress Intercept and MSW
But on the Cynon side, you have declarative convenience, and on the Jest side, you have imperative possibility. Let's now compare the network spy and mocking capabilities of Cypress Intercept and Mock Service worker. When mocking on the network side, you can gain more confidence in your component. Comparing the APIs, MSW requires more setup and hooks, while Cypress Intercept provides a simpler API with more flexibility. Although MSW is fantastic, Cypress Intercept does slightly better in mocking at a network level.
5. Comparing Developer Experience and Debugging
Some of these examples show that the more complex the component gets, the less code is needed with Cypress Intercept. Let's compare the developer experience by going through three simple examples, introducing artificial failures, and debugging them. In one example, we change the display from 'off' to 'on' and observe the test results. With Cypress, we can quickly identify the failure and debug it by inspecting the DOM.
6. Cypress Component Testing Stability
Can we close the test too? Let me jump to the input detail component to show you the test. We type 42 and want onChange to be called twice. For the read-only version, we ensure that we can't interact with it. We introduce an artificial delay to simulate a failure. The Cypress component test waits for three seconds and retries, making the test stable. Cypress component testing is more stable in CI compared to RTL.
7. RTL Test and Heroes Component
You can make it work on the RTL side, see input detail test. The static check isn't going to work. You're not getting these calls because this is a static check and it's failing on line 28. Once you use the WaitFor API wrapping that assertion in an async function, your test is going to be working better. So that is going to be the Heroes component. We're almost there with the RTL Passing Test of Input Detail. We'll just wait for it. In this one, we're testing the error component.
8. Developer Experience and Observability
The Cypress component test intercepts the network request and provides full observability into the component. In comparison, RTL lacks visibility and debugging capabilities. The developer experience with Cypress component testing is superior, as it allows for testing in a real browser and provides full observability. On the other hand, RTL leaves you in the dark. Overall, there are many similarities between the tools, but the key differentiator is the developer experience.
Cecilia Martinez, a technical account manager at Cypress, discusses network requests in Cypress and demonstrates commands like cydot request and SCI.INTERCEPT. She also explains dynamic matching and aliasing, network stubbing, and the pros and cons of using real server responses versus stubbing. The talk covers logging request responses, testing front-end and backend API, handling list length and DOM traversal, lazy loading, and provides resources for beginners to learn Cypress.
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