Embedded Test

The embedded-test library provides a test harness for embedded systems (riscv, arm and xtensa). Use this library on the target together with probe-rs on the host to run integration tests on your embedded device.

probe-rs together with embedded-test provide a (libtest compatible) test runner, which will:

1. Flash all the tests to the device in one go (via the probe-rs run command)
2. Request information about all tests from the device (via semihosting SYS_GET_CMDLINE)
3. In turn for each testcase:
   • Reset the device
   • Signal to the device (via semihosting SYS_GET_CMDLINE) which test to run
   • Wait for the device to signal that the test completed successfully or with error (via semihosting SYS_EXIT)
4. Report the results

Since the test runner (probe-rs run) is libtest compatible ( using libtest-mimic), you can use intellij or vscode to run individual tests with the click of a button.

Features

• Runs each test case individually, and resets the device between each test case
• Supports an init function which will be called before each test case and can pass state to the test cases
• Supports async test and init functions (needs feature embassy)
• Support #[should_panic], #[ignore] and #[timeout(<seconds>)] attributes for each test case

Usage

Add the following to your Cargo.toml:

[dev-dependencies]
embedded-test = { version = "0.4.0", features = ["init-log"] }


[[test]]
name = "example_test"
harness = false

Install the runner on your system:

cargo install probe-rs-tools

Add the following to your .cargo/config.toml:

[target.riscv32imac-unknown-none-elf]
runner = "probe-rs run --chip esp32c6"
# `probe-rs run` will autodetect whether the elf to flash is a normal firmware or a test binary

Add the following to your build.rs file:

fn main() {
    println!("cargo::rustc-link-arg-tests=-Tembedded-test.x");
}

Then you can run your tests with cargo test --test example_test or use the button in vscode/intellij.

Having trouble setting up? Checkout out the FAQ and common Errors Wiki page.

Example Test

Example repo
More Detailed Cargo.toml
Async Test Example

Example for tests/example_test.rs

#![no_std]
#![no_main]

#[cfg(test)]
#[embedded_test::tests]
mod tests {
    use esp_hal::{clock::ClockControl, delay::Delay, peripherals::Peripherals, prelude::*};

    // Optional: A init function which is called before every test
    #[init]
    fn init() -> Delay {
        let peripherals = Peripherals::take();
        let system = peripherals.SYSTEM.split();
        let clocks = ClockControl::max(system.clock_control).freeze();
        let delay = Delay::new(&clocks);

        // The init function can return some state, which can be consumed by the testcases
        delay
    }

    // A test which takes the state returned by the init function (optional)
    #[test]
    fn takes_state(_state: Delay) {
        assert!(true)
    }

    // Example for a test which is conditionally enabled
    #[test]
    #[cfg(feature = "log")]
    fn log() {
        log::info!("Hello, log!"); // Prints via esp-println to rtt
        assert!(true)
    }

    // Another example for a conditionally enabled test
    #[test]
    #[cfg(feature = "defmt")]
    fn defmt() {
        use defmt_rtt as _;
        defmt::info!("Hello, defmt!"); // Prints via defmt-rtt to rtt
        assert!(true)
    }

    // A test which is cfg'ed out
    #[test]
    #[cfg(abc)]
    fn it_works_disabled() {
        assert!(false)
    }

    // Tests can be ignored with the #[ignore] attribute
    #[test]
    #[ignore]
    fn it_works_ignored() {
        assert!(false)
    }

    // A test that fails with a panic
    #[test]
    fn it_fails1() {
        assert!(false)
    }

    // A test that fails with a returned Err(&str)
    #[test]
    fn it_fails2() -> Result<(), &'static str> {
        Err("It failed because ...")
    }

    // Tests can be annotated with #[should_panic] if they are expected to panic
    #[test]
    #[should_panic]
    fn it_passes() {
        assert!(false)
    }

    // This test should panic, but doesn't => it fails
    #[test]
    #[should_panic]
    fn it_fails3() {}

    // Tests can be annotated with #[timeout(<secs>)] to change the default timeout of 60s
    #[test]
    #[timeout(10)]
    fn it_timeouts() {
        loop {} // should run into the 10s timeout
    }
}

Configuration features

Feature	Default?	Description
panic-handler	Yes	Defines a panic-handler which will invoke semihosting::process::abort() on panic
defmt	No	Prints testcase exit result to defmt. You'll need to setup your defmt #[global_logger] yourself.
log	No	Prints testcase exit result to log. You'll need to setup your logging sink yourself (or combine with the init-log feature).
init-rtt	No	Calls rtt_target::rtt_init_print!() before starting any tests
init-log	No	Calls rtt_log::init(); before starting any tests.
embassy	No	Enables async test and init functions. Note: You need to enable at least one executor feature on the embassy-executor crate unless you are using the external-executor feature.
external-executor	No	Allows you to bring your own embassy executor which you need to pass to the #[tests] macro (e.g. #[embedded_test::tests(executor = esp_hal::embassy::executor::thread::Executor::new())])
xtensa-semihosting	No	Enables semihosting for xtensa targets.

License

Licensed under either of:

• Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.