| # Driver testing |
| |
| ## Manual hardware unit tests |
| |
| A driver may choose to implement the `run_unit_tests()` driver op, which |
| provides the driver a hook in which it may run unit tests at system |
| initialization with access to the parent device. This means the driver may test |
| its bind and unbind hooks, as well as any interactions with real hardware. If |
| the tests pass (the driver returns `true` from the hook) then operation will |
| continue as normal and `bind()` will execute. If the tests fail then the device |
| manager will assume that the driver is invalid and never attempt to bind it. |
| |
| Since these tests must run at system initialization (in order to not interfere |
| with the usual operation of the driver) they are activated with a |
| [kernel command line flag](/docs/reference/kernel/kernel_cmdline.md). To enable |
| the hook for a specific driver, use `driver.<name>.tests.enable`. Or for all |
| drivers: `driver.tests.enable`. If a driver doesn't implement `run_unit_tests()` |
| then these flags will have no effect. |
| |
| `run_unit_tests()` passes the driver a channel for it to write test output to. |
| Test output should be in the form of `fuchsia.driver.test.Logger` FIDL messages. |
| The driver-unit-test library contains a [helper class] that integrates with |
| zxtest and handles logging for you. |
| |
| [helper class]: /zircon/system/ulib/driver-unit-test/include/lib/driver-unit-test/logger.h |
| |
| ## Integration tests |
| |
| Driver authors can use several means for writing integration tests. For simple |
| cases, the [fake-ddk](/src/devices/testing/fake_ddk) library is recommended. For |
| more complicated ones, |
| [isolated-devmgr](/src/lib/isolated_devmgr) is |
| recommended. |
| |
| TODO(fxbug.dev/51320): Fill out more detail here. |
