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A: Use language-appropriate constructs, like GTest for C++. You can define a new file if need be, such as:
(in a BUILD.gn file)
executable("unittests") { output_name = "scenic_unittests" testonly = true sources = ["some_test.cc"], deps = [":some_dep"], }
A: Tests are represented as entries in the FUCHSIA_BUILD_DIR/tests.json
file generated by GN based on arguments of fx set
. The step that creates or updates tests.json
is called the gen phase of the build, and it is triggered by fx set
, fx build
or explicitly by fx gen
.
If fx test
doesn‘t find your test, first check FUCHSIA_BUILD_DIR/tests.json
. In most cases, the product configuration plus the --with
arguments of your fx set
commmand are missing, directly or transitively, the test that you are attempting to run. If that’s the case, just add the test GN label or a GN label that transitively has the test as an --with
argument to the fx set
command, for example:
fx set ... --with //src/sys:tests
If a newly added test is in the product configuration defined by fx set
but still doesn't show in tests.json
, you may need to run fx gen
or fx build
to update tests.json
so that fx test
knows how to run it.
There‘s the easy way if your QEMU has networking, and the hard way if it doesn’t.
A (with networking): In one terminal, start your QEMU instance with fx qemu -N
. Next, on another terminal, type in fx test scenic_tests
.
This invocation runs all the test executables in the scenic_tests
package.
A (no networking): Start a QEMU instance (fx qemu
), and then manually invoke the runtests
command.
In the QEMU shell, type in run-test-component scenic_tests
. The argument is a specific directory containing the test executables.
Note Well! Without networking, the files are loaded into the QEMU instance at startup. So after rebuilding a test, you'll need to shutdown and re-start the QEMU instance to see the rebuilt test.
To exit QEMU, dm shutdown
.
A: Either manual invocation, like in QEMU, or fx test
to a running device.
Note that the booted device may not contain your binary at startup, but fx test
will build the test binary, ship it over to the device, and run it, while piping the output back to your workstation terminal. Slick!
Make sure your device is running (hit Ctrl-D to boot an existing image) and connected to your workstation.
From your workstation, fx test scenic_tests
will serially run through all test executables contained in the scenic_tests
package.
To run just one test executable, use the following command:
fx test <executable-name>
Note: To run a unit test, the deprecated fx run-test
command used the -t
flag. To learn more about the new fx test
command, see Run Fuchsia tests.
You can automatically rebuild, install, and run your tests on every source file change with fx -i
. For instance: fx -i test scenic_tests
.
A: The output is directed to your terminal.
There does exist a way to write test output into files (including a summary JSON file), which is how CQ bots collect the test output for automated runs.
A: There are several ways to do this. Whenever doing any of these, be sure to file a bug and reference that bug in a comment in the code that disables the test.
You can do this by adding “flaky” to the tags
field in the test environment. This operates on the entire test target (which corresponds to an executable). It will prevent this target from running on the builders in the commit queue, and enable the target on special flaky builders that continue to run the test in CI. Be sure to note the bug in a comment in the BUILD.gn file. Example change.
If you want to disable only some tests that are part of a larger test target, you'll need to split the target into two GN targets, and tag one as flaky.
To disable a particular test inside of a larger test executable, you can mark it as disabled. Disabled tests are defined by having their name prefixed with DISABLED_
. One way to find them is therefore simply git grep DISABLED_
.
If running the test outputs YOU HAVE 1 DISABLED TEST
, you can also pass the following flags to find out which test is disabled: fx run-test scenic_tests -- --gtest_list_tests --gtest_filter=*DISABLED_*
.
To force-run disabled tests: fx run-test scenic_tests -- --gtest_also_run_disabled_tests
.
#[ignore]
attributeTo disable a particular test inside of a larger Rust test executable, you can tag it with #[ignore]
. It should be applied underneath the #[test]
attribute.
Example:
#[test] #[ignore] // TODO(fxbug.dev/NNNNN) re-enable this test when de-flaked fn flaky_test_we_need_to_fix() { ... }
Alternatively, you may also disable an entire test executable within a package containing several test executables. To do this, edit the BUILD.gn
as follows: tests = [ { name = "scenic_unittests", disabled = true } ]
. As a result, scenic_unittests
will be put in a disabled
sub-directory of /pkgfs/packages/<package_name>/0/test
, and will not be run by the CQ system.
To disable a particular test inside of a larger test executable, you can comment out the code that defines that test.
A: Unlike the fx run-test
command, the primary feature of fx test
is batch execution. See Run Fuchsia tests for examples on how to run multiple tests or test suites together.
Additionally, you can always upload your patch to Gerrit and do a CQ dry run.
A: Clicking on CQ dry run (aka +1) will take your change's properly defined unit test and run it on multiple bots, one for each build target (x86-64 versus arm64, release versus debug). Each job will have an output page showing all the tests that ran.
A: The simplest artifact is just a file that is in your source directory. For this you just need to add it to resources
attribute of the package definition of your unit test. For example, you may do something like this in your BUILD.gn
:
rustc_binary("my-great-app") { with_unit_tests = true ... } test_package("my-great-app-tests") { deps = [ ":my-great-app_test", ] resources = [ { path = "source.zip" dest = "testing.zip" } ]
The file will be available as /pkg/data/testing.zip
inside the environment where the test binary will be executed.
TODO: If you want an artifact that is generated as part of the build process, you should probably add the rule that generates the artifact to the data_deps
array of the test_package
rule. But I have not tried it yet. Update this section when you will try it :)