If you find this helpful, please like, bookmark, and follow. To keep learning along, follow this series. 11.1.1 What Is Testing In Rust, a test is a function used to verify whether non-test code behaves as expected. A test function usually performs three actions: Arrange data/state Act on the code under test Assert the result In some languages, these three actions are called the 3A steps. 11.1.2 Anatomy of a Test Function A test function is still just a function; the difference is that it must be annotated with the test attribute. An attribute is metadata for Rust code. It does not change the logic of the code it decorates; it only adds decoration, or annotation. In fact, we already used this in 5.2. Struct Usage Example - Printing Debug Information. Adding #[test] to a function turns it into a test function. 11.1.3 Running Tests Putting aside what is inside the test function for now, how do we run it after writing it? We use the cargo test command to run all tests.…