# Testing

## Quick Start

To build Zircon and run unit tests, run one of the following commands:

```sh
# Build and run x64.
fx set bringup.x64 --with-base //bundles/buildbot:bringup
fx build
fx qemu

# Build and run arm64.
fx set bringup.arm64 --with-base //bundles/buildbot:bringup
fx build
fx qemu
```

Once the scripts finish running, you should see the Zircon shell. To run
userspace tests, use the Zircon shell to run:

```sh
runtests --all
```

You can use `runtests --all -d` to see the list of tests available in the
system. You can also use `runtests -n <TEST_NAME>` to run one specific test.

To run in-kernel tests, use the Zircon shell to run:

```sh
k ut all
```

Fuchsia's [Get Started](/docs/get-started/index.md) page has more details about how to
use the Zircon shell and how to automatically build all supported architectures.

## Userspace Tests

The test harness, runtests, picks up and runs all of the executables from the
`/boot/test` and `/system/test` directories. If you provide a command-line
argument, such as `runtests -m widget_test`, runtests will only run the
single test requested -- in this case, `widget_test`.

## Kernel-mode Tests

The kernel contains unit tests and diagnostics, which can be run using the `k`
command. The output of the `k` command will only be shown on the
console. Depending on your configuration, this might be the serial console, or
the `debuglog` virtual terminal.

### Unit tests

Many parts of the kernel have unit tests, which report success/failure
automatically. These unit tests are built using the primitives provided by [the
kernel unit-test library](/zircon/kernel/lib/unittest/). You can find these statically
by searching for `UNITTEST_START_TESTCASE`.

These tests can be run from the shell with `k ut`. `k ut all` will run all tests
or you can use `k ut $TEST_NAME` to run a specific test.

### Diagnostics

Many parts of the kernel provide diagnostics, whose output requires manual
inspection. Some of these diagnostics are used to verify correctness
(e.g. [`timer_diag`](/zircon/kernel/tests/timer_tests.cc)), while others simply
stress test a part of the system
(e.g. [`timer_stress`](/zircon/kernel/tests/timer_tests.cc)).

To run a diagnostic, simply pass its name to the `k` command. For example, to
run the kernel's [builtin benchmarks](/zircon/kernel/tests/benchmarks.cc), run `k
bench`. To find the full set of kernel diagnostics statically, search for
`STATIC_COMMAND`. To enumerate them dynamically, run `k help`.

Diagnostic tests are intended to be run via serial console, or with physical
access to the system. Some diagnostics may be destructive, and leave the system
in a broken state.