Test Vitest

[Olympia Brackin]

Itis recommended that you install a copy of vitest in your package.json, using one of the methods listed above. However, if you would prefer to run vitest directly, you can use npx vitest (the npx tool comes with npm and Node.js).

The npx tool will execute the specified command. By default, npx will first check if the command exists in the local project's binaries. If it is not found there, npx will look in the system's $PATH and execute it if found. If the command is not found in either location, npx will install it in a temporary location prior to execution.

One of the main advantages of Vitest is its unified configuration with Vite. If present, vitest will read your root vite.config.ts to match with the plugins and setup as your Vite app. For example, your Vite resolve.alias and plugins configuration will work out-of-the-box. If you want a different configuration during testing, you can:

If you decide to have two separate config files for Vite and Vitest, make sure to define the same Vite options in your Vitest config file since it will override your Vite file, not extend it. You can also use mergeConfig method from vite or vitest/config entries to merge Vite config with Vitest config:

Run different project configurations inside the same project with Vitest Workspaces. You can define a list of files and folders that define your workspace in vitest.workspace file. The file supports js/ts/json extensions. This feature works great with monorepo setups.

To run tests once without watching for file changes, use vitest run. You can specify additional CLI options like --port or --https. For a full list of CLI options, run npx vitest --help in your project.

Vitest 1.3.0 deprecates the use of options as the last parameter. You will see a deprecation message until 2.0.0 when this syntax will be removed. If you need to pass down options, use test function's second argument:

In Jest, TestFunction can also be of type (done: DoneCallback) => void. If this form is used, the test will not be concluded until done is called. You can achieve the same using an async function, see the Migration guide Done Callback section.

Use test.extend to extend the test context with custom fixtures. This will return a new test and it's also extendable, so you can compose more fixtures or override existing ones by extending it as you need. See Extend Test Context for more information.

In some cases you might run tests multiple times with different environments, and some of the tests might be environment-specific. Instead of wrapping the test code with if, you can use test.skipIf to skip the test whenever the condition is truthy.

When you use test or bench in the top level of file, they are collected as part of the implicit suite for it. Using describe you can define a new suite in the current context, as a set of related tests or benchmarks and other nested suites. A suite lets you organize your tests and benchmarks so reports are more clear.

In some cases, you might run suites multiple times with different environments, and some of the suites might be environment-specific. Instead of wrapping the suite with if, you can use describe.skipIf to skip the suite whenever the condition is truthy.

Vitest provides a way to run all tests in random order via CLI flag --sequence.shuffle or config option sequence.shuffle, but if you want to have only part of your test suite to run tests in random order, you can mark it with this flag.

These functions allow you to hook into the life cycle of tests to avoid repeating setup and teardown code. They apply to the current context: the file if they are used at the top-level or the current suite if they are inside a describe block. These hooks are not called, when you are running Vitest as a type checker.

This hook is always called after the test has finished running. It is called after afterEach hooks since they can influence the test result. It receives a TaskResult object with the current test result.

This hook is called only after the test has failed. It is called after afterEach hooks since they can influence the test result. It receives a TaskResult object with the current test result. This hook is useful for debugging.

If you have worked with other testing libraries such as Jest, Mocha or Jasmine, you should be familiar with the BDD (Behavior Driven Development) pattern.It describes a function, explains what it does and uses test case(s) to assert that it works as intended.

Vitest is often compared to Jest, another popular test framework.It is because it is built on top of Jest, making it a more modern and improved version.Also, it offers compatibility with most of the Jest API and ecosystem libraries, making it simple to migrate by following their official guide here.

Just like other widely used test frameworks such as Mocha and Jasmine, Vitest follows a simple describe-it-assert or describe-it-expect pattern.The advantage of using Vitest over them is that it is fast to set up and does not require installing a separate assertion library.

The most convenient advantage of using Vitest is that it requires minimal configuration and can be used with any bundler.You can define the configuration for your dev, build and test environments as a single pipeline under vite.config.js.

In this article, we learned about Vitest, a fast and modern unit testing framework powered by Vite.Thanks for reading, I hope it has been a helpful article in getting you started with Vitest.Please refer to the References section below if you would like to read more about Vitest and Vite. Cheers!

I have multiple test files in the project, let's say A.spec.ts and B.spec.test. I am using the standard test script (vitest run --no-threads --coverage) to test my code. I want to run a certain function (to purge and clean the testing database), before and after all the test suites are run (i.e. before all the tests in A.spec.ts and B.spec.ts, and after them as well).

Ok, so what we would like to do now is render the component and start testing it. For that we need the equivalent of the react-testing-library for solid, which is (sit down for this) Solid-Testing-Library.

Adding it to my dev dependencies and moving on -

Hi, here's Alex, the regular solid.js testing guy. Thanks for that article, because I haven't found the time to update mine, but I wanted to update our vite plugin first so vitest is supported out of the box again. Maybe you want to join my efforts?

run-p allows us to run scripts in parallel and db:migrate:* tells npm to run all scripts that start with the db:migrate: prefix. This makes sure that everytime we migrate our development database, the new schema is pushed to our test database.

When developing Vue applications, we use one or more components to ensure our code is easy to read and maintain. Verifying whether a component executes as expected without error is essential where application functionality and performance matter.

There are many automated testing frameworks we can use for testing Vue components, such as Vitest, Jest, Cypress, etc. the Vue team recommends using Vitest to test Vue applications because of its unique features. Vitest is created and maintained by Vue and Vite team members.

Now, we need to create a test file for our component. As a naming convention, the test file name has to start with the component name and end with .spec.js or .test.js. Each component should have a test file when testing multiple components.

A snapshot is used to keep track of changes in the user interface. A typical snapshot test case renders a UI component, takes a snapshot, and compares it to a reference snapshot file alongside the test. It compares the current state of your UI to the established snapshots. The test will fail if the current state does not match the established state.

Migrating your application tests from Jest to Vitest is very straightforward. Both testing frameworks use similar APIs, so you may not need to make significant changes to your existing code when migrating to Vitest.

I had originally planned to keep using Jest during the migration of CRA to ViteJS, but I kept running into issues, mainly because Jest support for ES Modules is still experimental. There is a Vite plugin called vite-jest but it's still very much a work in progress.

Vitest is also pretty early in its development stages, but I felt that it was stable enough to give it a try, and I'm sure glad I did. It has many advantages but one thing I really like about it compared to other test runners is that it shares the same config file and plugins as Vite itself, so there's only one single pipeline to worry about.

Vitest has been designed with a Jest compatible API (describe, expect, it, should etc.), so migrating tests was an absolute breeze. Unless you mock modules or methods, you probably won't need to do anything here.

Overall I'm extremely happy with Vitest, they've really made the migration so easy. I'm even more impressed with their docs given it's still pretty new, especially the number of examples they have. If you found this article helpful or have suggestions, please leave a comment below. ?

Good to know: Since async Server Components are new to the React ecosystem, Vitest currently does not support them. While you can still run unit tests for synchronous Server and Client Components, we recommend using an E2E tests for async components.

For the first time, you can write unit tests that run within the same runtime that Cloudflare Workers run on in production, providing greater confidence that the behavior of your Worker in tests will be the same as when deployed to production. For integration tests, you can now write tests for Workers that are triggered by Cron Triggers in addition to traditional fetch() events. You can also more easily test complex applications that interact with KV, R2, D1, Queues, Service Bindings, and more Cloudflare products.

With the new Workers Vitest Integration, you can test anything exported from your Worker in both unit and integration-style tests. Within these tests, you can also test connected resources like R2, KV, and Durable Objects, as well as applications involving multiple Workers.

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