spin-test

spin-test is a plugin for Spin that runs tests written in WebAssembly against a Spin application where all Spin and WASI APIs are configurable and assertable mocks.

Usage

spin-test can be used as a stand alone binary or as a plugin for Spin.

Before using spin-test, make sure you've installed Spin.

Install spin test (Spin plugin)

To install spin-test as a Spin plugin, run the following:

spin plugin install -u https://github.com/fermyon/spin-test/releases/download/canary/spin-test.json

This will install the plugin which can be invoked with spin test.

Currently only a canary version (that matches the code on the main branch) is available at this time. This does mean that breaking changes may come with any upgrade of the plugin. In the future, stable, non-canary releases will also be made available.

Or install a locally built version

To install a version of spin-test plugin that has been locally built using cargo build --release, use the following command:

spin pluginify -i

Note: the pluginify plugin is a pre-requisite.

Or install spin-test (stand alone)

Alternatively, to install spin-test as a stand alone binary, run cargo build --release from this directory and ensure that the resulting binary is located on your path.

If you'd rather not build from source, you can find a pre-built binary inside the plugin tarballs included in any release. In the latest stable release or in the canary release, find the tarball asset corresponding to the appropriate machine architecture, download the tarball, unarchive it, and retrieve the test binary inside it. Place this binary somewhere on your path as spin-test and invoke by running spin-test.

Create a Spin App

spin-test runs tests against a Spin application. As such, you'll need a Spin app to test against. You can find more information on creating Spin applications here.

Create a spin-test test

Next you'll need a spin-test test compiled to a WebAssembly component.

There is currently first class support for Rust through the spin-test Rust SDK, but any language with support for writing WebAssembly components can be used as long as the fermyon:spin-test/test world is targeted. You can find the definition of this world in here.

You can see examples of tests written in a variety of languages in the examples.

Configure spin-test

Next, we'll need to tell spin-test where our test lives and how to build it. We do this from inside the spin.toml manifest. Let's imagine our app has a component named "my-component" that we want to test. In the spin.toml manifest we can add the following configuration:

[component.my-component.tool.spin-test]
# A relative path to where the built test component binary will live.
source = "target/wasm32-wasi/release/test.wasm"
# A command for building the target component.
build = "cargo component build --release"
# The directory where the `build` command should be run.
workdir = "../../test-rs"

Run spin test

Finally, we're ready for our test to be run. We can do this simply by invoking the spin test plugin from the directory where our Spin application lives:

spin test

Note: if you've installed spin-test as a stand alone binary instead of as a Spin plugin, you'll need to invoke it as spin-test instead of with a space like spin test.

Examples

See the examples directory for a few examples of spin-test tests that test the apps in the apps directory.