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Testsuite Customization

Prerequisites

Testsuite Customization

Now that you have a running testsuite, you’ll want to start customizing the testsuite to your needs. Here we’ll walk through the components inside a testsuite, as well as how to customize them.

NOTE: This tutorial will avoid language-specific idioms and use a Java-like pseudocode notation in this documentation, but will reference the example in the Go implementation to illustrate. All object names and methods will be more or less the same in your language of choice, and all language repos come with an example testsuite.

Tests & Test Setup

First, we need to write a test. Each test is simply an implementation of the Test interface, and each has a Test.setup method which performs the work necessary to setup the testnet to a state where the test can run over it. You should use the NetworkContext.addService method to create instances of your service like this.

The addService call returns a ServiceContext object, which will contain the IP address of the service started so that you can wrap it in the appropriate client for your service (e.g. the Go Elasticsearch client). If your client doesn’t have a way to check if the service is available, you can use the provided NetworkContext.waitForAvailability method as a convenience to wait until your service is available.

Finally, the Test.setup method must return a Network object. This returned object will be the same one passed in as an argument to the Test.run method, which the test can use to interact with the network. For now, you can return the NetworkContext object.

Go ahead and create your own Test implementation now, with a Test.setup method that sets up the network you’d like to test.

Test Logic

Every implementation of the Test interface must fill out the Test.run method. This function takes in the Network object that was returned by Test.setup, and uses the methods on the TestContext object to make assertions about the state of the network like so. If no failures are called using the TestContext, the test is assumed to pass.

You should now fill in your test’s run method with logic to query and make assertions on your test network.

Test Suite

Now that you have a test, you’ll need to package it into a testsuite. A testsuite is simply an implementation of the TestSuite interface that yields a set of named tests, like this. This is also where you’ll thread through parameterization, like what Docker image the tests should run with.

You can go ahead and create your own TestSuite implementation now, to contain your test.

Test Suite Executor & Configurator

Finally, you’ll need to tell Kurtosis how to initialize your testsuite. All test suites are run via the TestSuiteExecutor class, which is configured at construction time with an instance of the TestSuiteConfigurator interface. This configurator class is responsible for doing things like setting the log level and constructing the instance of your testsuite from custom params (more on these later), so you’ll need to create your own implementation like this.

You should create your own TestSuiteConfigurator implementation now, to tell Kurtosis how to create your testsuite.

Main Function

With your testsuite configurator complete, your only remaining step is to make sure it’s getting used. When you bootstrapped your testsuite repo, you will have received an entrypoint main function that runs the testsuite executor like this Go example. You will also have received a Dockerfile, for packaging that main CLI into a Docker image (Go example).

What build-and-run.sh actually does during its “build” phase is compile the main entrypoint CLI and package it into an executable Docker image. In order for your testsuite to get run, you just need to make sure this main entrypoint CLI is using your TestsuiteConfigurator by slotting in your configurator where indicated.

Congratulations - you now have your custom testsuite running using Kurtosis!

Custom Networks

So far your Test.setup method has returned the Kurtosis-provided NetworkContext, and your Test.run method has consumed it. This can be enough for basic tests, but you’ll often want to centralize the network setup logic into a custom object that all your tests will use. Kurtosis allows this by letting your Test.setup method return any implementation of the Network marker interface; the Test.run will then receive that same Network object as an argument. To see this in action, the Go example testsuite has this custom Network object, which makes the Test.setup of complex networks a whole lot simpler by encapsulating all the container-starting and availability-checking.

If you’d like, you can extract your test’s Test.setup logic into a custom Network implementation to make your custom test code cleaner.

Custom Parameterization

You’ll notice that the TestsuiteConfigurator.parseParamsAndCreateSuite method takes in a “params JSON” argument. This is arbitrary data that you can pass in to customize your testsuite’s behaviour (e.g. which tests get run, or which Docker images get used). The data you pass in here is up to you, and is set via the --custom-params flag when calling build-and-run.sh. To see this in action, look at how the example parses the args to a custom object that it uses to instantiate the testsuite.

If your testsuite needs custom parameters (e.g. the name of the Docker images to your test network), you can parameterize your TestSuite implementation and consume them in your custom executor.

Visual Overview

To provide a visual recap of everything you’ve done, here’s a diagram showing the control flow between components:


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