Test Writing

Keep in mind that it's impossible to find all bugs.

Tests are the last line of defense.

Unit Tests

Unit tests are small, focused tests that verify the behavior of a single function or module in isolation.

Example:

// ...Other Codes

#[cfg(test)] // indicates this block will only be compiled when running tests
mod tests {
   use super::*;

   #[test] // indicates that this function is a test, which will be run by `cargo test`
   fn test_add() {
      let result = add(1, 1);
      assert_eq!(result, 2); // assert is important to tests
   }
}

Integration Tests

Integration tests verify that different parts of your library work correctly together. They are external to your crate and use your code in the same way any other code would.

Steps

You can refer to the implementation of the mega module. (mega/tests)

1. Create a tests directory at the same level as your src directory (e.g. libra/tests).
2. Add *.rs files in this directory. // Each file will be compiled as a separate crate.

Attention

• The tests in root directory (workspace) is NOT integration tests, but some data for other tests.
• If you need a common module, use tests/common/mod.rs rather than tests/common.rs, to declare it's not a test file.
• There is no need to add #[cfg(test)] to the tests directory. tests will be compiled only when running tests.

Run integration tests

The following command will be executed in GitHub Actions.

This command DOES NOT run Unit Tests (which could be very messy).

cargo test --workspace --test '*' -- --nocapture

• --workspace : Run tests for all packages in the workspace.
• --test : Test the specified integration test.
• -- : Pass the following arguments to the test binary.
• --nocapture : DO NOT capture the output (e.g. println!) of the test.

If you want to run tests in a specific package, you can use --package.

For more information, please refer to the rust wiki.