Learn how to use continuous testing in your Quarkus Application.

1. Prerequisites

To complete this guide, you need:

  • Roughly 15 minutes

  • An IDE

  • JDK 11+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.8.4

  • Optionally the Quarkus CLI if you want to use it

  • Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)

  • The completed greeter application from the Getting Started Guide

2. Introduction

Quarkus supports continuous testing, where tests run immediately after code changes have been saved. This allows you to get instant feedback on your code changes. Quarkus detects which tests cover which code, and uses this information to only run the relevant tests when code is changed.

3. Solution

Start the Getting Started application (or any other application) using:

CLI
quarkus dev
Maven
./mvnw quarkus:dev
Gradle
./gradlew --console=plain quarkusDev

Quarkus will start in development mode as normal, but down the bottom of the screen you should see the following:

--
Tests paused, press [r] to resume, [h] for more options>

Press r and the tests will start running. You should see the status change down the bottom of the screen as they are running, and it should finish with:

--
Tests all passed, 2 tests were run, 0 were skipped. Tests took 1470ms.
Press [r] to re-run, [v] to view full results, [p] to pause, [h] for more options>
If you want continuous testing to start automatically you can set quarkus.test.continuous-testing=enabled in application.properties. If you don’t want it at all you can change this to disabled.

Now you can start making changes to your application. Go into the GreetingResource and change the hello endpoint to return "hello world", and save the file. Quarkus should immediately re-run the test, and you should get output similar to the following:

2021-05-11 14:21:34,338 ERROR [io.qua.test] (Test runner thread) Test GreetingResourceTest#testHelloEndpoint() failed
: java.lang.AssertionError: 1 expectation failed.
Response body doesn't match expectation.
Expected: is "hello"
  Actual: hello world

	at io.restassured.internal.ValidatableResponseImpl.body(ValidatableResponseImpl.groovy)
	at org.acme.getting.started.GreetingResourceTest.testHelloEndpoint(GreetingResourceTest.java:21)


--
Test run failed, 2 tests were run, 1 failed, 0 were skipped. Tests took 295ms
Press [r] to re-run, [v] to view full results, [p] to pause, [h] for more options>

Change it back and the tests will run again.

4. Controlling Continuous Testing

There are various hotkeys you can use to control continuous testing. Pressing h will display the following list of commands:

The following commands are available:
[r] - Re-run all tests
[f] - Re-run failed tests
[b] - Toggle 'broken only' mode, where only failing tests are run (disabled)
[v] - Print failures from the last test run
[p] - Pause tests
[o] - Toggle test output (disabled)
[i] - Toggle instrumentation based reload (disabled)
[l] - Toggle live reload (enabled)
[s] - Force restart
[h] - Display this help
[q] - Quit

These are explained below:

[r] - Re-run all tests

This will re-run every test

[f] - Re-run failed tests

This will re-run every failing test

[b] - Toggle 'broken only' mode, where only failing tests are run

Broken only mode will only run tests that have previously failed, even if other tests would normally be affected by a code change. This can be useful if you are modifying code that is used by lots of tests, but you only want to focus on debugging the failing one.

[v] - Print failures from the last test run

Prints the failures to the console again, this can be useful if there has been lots of console output since the last run.

[p] - Pause tests

Temporarily stops running tests. This can be useful if you are making lots of changes, and don’t want feedback until they are all done.

[o] - Toggle test output

By default test output is filtered and not displayed on the console, so that test output and dev mode output is not interleaved. Enabling test output will print output to the console when tests are run. Even when output is disabled the filtered output is saved and can be viewed in the Dev UI.

[i] - Toggle instrumentation based reload

This is not directly related to testing, but allows you to toggle instrumentation based reload. This will allow live reload to avoid a restart if a change does not affect the structure of a class, which gives a faster reload and allows you to keep state.

[l] - Toggle live reload

This is not directly related to testing, but allows you to turn live reload on and off.

[s] - Force restart

This will force a scan for changed files, and will perform a live reload with and changes. Note that even if there are no changes the application will still restart. This will still work even if live reload is disabled.

5. Continuous Testing Without Dev Mode

It is possible to run continuous testing without starting dev mode. This can be useful if dev mode will interfere with your tests (e.g. running wiremock on the same port), or if you only want to develop using tests. To start continuous testing mode run mvn quarkus:test.

The Dev UI is not available when running in continuous testing mode, as this is provided by dev mode.

6. Multi Module Projects

Note that continuous testing supports multi-module projects, so tests in modules other than the application can still be run when files are changed. The modules that are run can be controlled using config as listed below.

This is enabled by default, and can be disabled via quarkus.test.only-test-application-module=true.

7. Configuring Continuous Testing

Continuous testing supports multiple configuration options that can be used to limit the tests that are run, and to control the output. The configuration properties are shown below: