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]
    fn test_panic() {
        test::assert_panics!(panic!("oops"));
    }
}
Run this example

Test attributes

The following attribute is supported: #[test::ignore] to skip execution of a test (useful e.g. to make sure that a test compiles but is not run). This can be used in combination with #[cfg_attr(...)] to conditionally enable a test only on certain configurations.

#[cfg_attr(not(target_arch = "x86_64"), test::ignore)]
fn test_is_x86_64() {
    assert_eq!(cfg!(target_arch), "x86_64");
}
Run this example

Custom test frameworks

Nothing prevents you from writing your own framework, just compile with --cfg custom_test_framework. The TestCase and TEST_CASES constants are public and can be used to implement custom test runners, or they can be discovered through reflection in a different way. cases.

Modules

Structs

Functions

• #[cfg] fn main(args: &[&[u8]]) -> i32

  source

  Test runner entrypoint.

Macros

Consts

• const TEST_CASES = /* ... */

  source

  List of all discovered test cases