Module test

Minimal unit test runner

When --cfg test is provided as an argument to the compiler, this module will override the main entrypoint with the test runner which will run all the test cases defined in the code that is being compiled.

Each test case is executed in a subprocess.

Example

fn add(x: i32, y: i32) -> i32 {
    x + y
}

fn sub(x: i32, y: i32) -> i32 {
    x - y
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_add() {
        assert_eq!(1.add(2), 3);
    }

    #[test]
    fn test_sub() {
        assert_eq!(1.sub(2), -1);
    }

    #[test(should_fail)]
    fn test_panic() {
        panic!("oops");
    }
}
Run this example

Test attributes

The following attributes are supported: #[test(ignore)] to skip execution of a test (useful e.g. to make sure that a test compiles but is not run), #[test(should_fail)] to mark a test as expected to fail (e.g. through panic).

Custom test frameworks

Nothing prevents you from writing your own framework, just compile with --cfg custom_test_framework and use the test support glue in runtime to get the test cases.

Modules

Structs

Functions

• fn should_fail(test: &TestCaseMeta) -> bool

  source

  Whether a failure (non-0 exit code) is expected for this test.

• fn ignored(test: &TestCaseMeta) -> bool

  source

  Whether a test should be ignored.

• fn run(test: &TestCaseMeta) -> TestResult

  source

  Run a single test case in a forked process and collect output.

• fn print_help_string(args: &[&[u8]]) -> !

  source

• fn parse_args(args: &[&[u8]]) -> Args

  source

  Parse command line arguments.

• fn filter_tests(args: Args) -> (Vector<TestCaseMeta>, usize)

  source

  Filter tests based on user-provided criteria (e.g. path prefix).

• fn main(args: &[&[u8]]) -> i32

  source

  Test runner entrypoint.