This document describes how to run a test component using the Fuchsia emulator (FEMU).
A component instance is started in Fuchsia when another component requests a capability from it. For example, the test manager (which is a component) starts a test component in response to a request to run a test.
This guide uses the
component in the
basic example package. When you
run this package’s
hello-world-tests test suite, the test manager starts the
hello-world-bin-test component. As a result, the component’s test binary runs
on a Fuchsia device, or in this case, on the Fuchsia emulator.
The steps to run a test component are:
Before you can run this test component, you must:
Build a Fuchsia image
Configure and build your Fuchsia image to include the test component:
To include a specific component, run the
fx setcommand with the
fx set core.qemu-x64 --with //examples/components/basic:hello-world-tests
//examples/components/basicis the directory of the example package and
hello-world-testsis the name of the build target defined in the package's
Build your Fuchsia image:
fx buildcommand completes, your new Fuchsia image now includes the
hello-world-bin-testcomponent, which can be fetched and launched on demand.
Start the emulator
Start the emulator with your Fuchsia image and run a package repository server:
In a new terminal, start the emulator:
fx emu -N
Set the emulator to be your device:
If you have multiple devices, select
fuchsia-5254-0063-5e7a(the emulator’s default device name), for example:
$ fx set-device Multiple devices found, please pick one from the list: 1) fuchsia-4407-0bb4-d0eb 2) fuchsia-5254-0063-5e7a #? 2 New default device: fuchsia-5254-0063-5e7a
In another new terminal, start a package repository server:
fx servecommand running as a package server for your device.
Run the test suite
hello-world-tests test suite:
fx test hello-world-tests
This command prints the following output:
$ fx test hello-world-tests ... [0/1] 00:00 🤔 /home/fuchsia/.jiri_root/bin/fx shell run-test-suite fuchsia-pkg://fuchsia.com/hello-world-tests#meta/hello-world-bin-test.cm >> Runtime has exceeded 2 seconds (adjust this value with the -s|--slow flag) Running test 'fuchsia-pkg://fuchsia.com/hello-world-tests#meta/hello-world-bin-test.cm' [RUNNING] tests::assert_0_is_0 [PASSED] tests::assert_0_is_0 1 out of 1 tests passed... fuchsia-pkg://fuchsia.com/hello-world-tests#meta/hello-world-bin-test.cm completed with result: PASSED [1/1] 00:05 ✅ /home/fuchsia/.jiri_root/bin/fx shell run-test-suite fuchsia-pkg://fuchsia.com/hello-world-tests#meta/hello-world-bin-test.cm 🎉 Ran 1 tests with 0 failures (use the -v flag to see each test) 🎉
The output shows that the
hello-world-bin-test component is fetched from the
package repository server and the component instance runs the test binary on the
Fuchsia device (the emulator). See
for the source code of this test binary.