defmt-test 0.1.1

A test harness for embedded devices
Documentation

defmt-test

a test harness for embedded devices

Basic usage

  1. If you don't have a project setup yet, start from the app-template, then proceed with step 3. If you have a project based on an old version of app-template then proceed with step 1.
  1. In the testsuite crate, add defmt-test to the dependencies:
 # testsuite/Cargo.toml

 [dependencies]
+ defmt-test = "0.1.0"
  1. Within the testsuite/tests/test.rs file, create a tests module and mark it with the #[defmt_test::tests] attribute. Within that module write std-like unit tests: functions marked with the #[test] attribute.
// testsuite/tests/test.rs

#[defmt_test::tests]
mod tests {
    #[test]
    fn assert_true() {
        assert!(true)
    }

    #[test]
    fn assert_false() {
        assert!(false, "TODO: write actual tests")
    }
}
  1. Run cargo test -p testsuite to run the unit tests
$ cargo test -p testsuite
(..)
0.000000 INFO  running assert_true ..
└─ test::tests::__defmt_test_entry @ tests/test.rs:7
0.000001 INFO  .. assert_true ok
└─ test::tests::__defmt_test_entry @ tests/test.rs:7
0.000002 INFO  running assert_false ..
└─ test::tests::__defmt_test_entry @ tests/test.rs:7
0.000003 ERROR panicked at 'TODO: write actual tests', testsuite/tests/test.rs:16:9
└─ panic_probe::print_defmt::print @ (..omitted..)
stack backtrace:
   0: HardFaultTrampoline
      <exception entry>
   1: __udf
   2: cortex_m::asm::udf
        at (..omitted..)
   3: rust_begin_unwind
        at (..omitted..)
   4: core::panicking::panic_fmt
        at (..omitted..)
   5: core::panicking::panic
        at (..omitted..)
   6: test::tests::assert_false
        at tests/test.rs:16
   7: main
        at tests/test.rs:7
   8: ResetTrampoline
        at (..omitted..)
   9: Reset
        at (..omitted..)

NOTE unit tests will be executed sequentially

Adding state

An #[init] function can be written within the #[tests] module. This function will be executed before all unit tests and its return value, the test suite state, can be passed to unit tests as an argument.

// state shared across unit tests
struct MyState {
    flag: bool,
}

#[defmt_test::tests]
mod tests {
    #[init]
    fn init() -> super::MyState {
        // state initial value
        super::MyState {
            flag: true,
        }
    }

    // this unit test doesn't access the state
    #[test]
    fn assert_true() {
        assert!(true);
    }

    // but this test does
    #[test]
    fn assert_flag(state: &mut super::MyState) {
        assert!(state.flag)
    }
}

$ cargo test -p testsuite
0.000000 INFO  running assert_true ..
└─ test::tests::__defmt_test_entry @ tests/test.rs:11
0.000001 INFO  .. assert_true ok
└─ test::tests::__defmt_test_entry @ tests/test.rs:11
0.000002 INFO  running assert_flag ..
└─ test::tests::__defmt_test_entry @ tests/test.rs:11
0.000003 INFO  .. assert_flag ok
└─ test::tests::__defmt_test_entry @ tests/test.rs:11

Support

defmt-test is part of the Knurling project, Ferrous Systems' effort at improving tooling used to develop for embedded systems.

If you think that our work is useful, consider sponsoring it via GitHub Sponsors.

License

Licensed under either of

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 licensed as above, without any additional terms or conditions.