How to use test-case crate for parameterized tests

The test-case crate allows you to run a single test function multiple times with different arguments using the #[test_case(...)] macro. Add the crate to your Cargo.toml, import the macro, and decorate your test function with the macro to define input parameters and expected results.

use test_case::test_case;

#[test_case(2, 2 => 4)]
#[test_case(5, 10 => 15)]
fn add(a: i32, b: i32) -> i32 {
    a + b
}

1. Add the dependency to your Cargo.toml file. cargo add test-case

2. Import the test_case macro in your test module. use test_case::test_case;

3. Apply the #[test_case] attribute above your test function with arguments and expected output. #[test_case(2, 2 => 4)]

4. Run the tests using the standard cargo test command. cargo test

The test-case crate lets you write one test function that runs automatically with many different sets of data. Instead of copying and pasting your test code for every scenario, you just list the inputs and expected results above the function. It is like having a spreadsheet where each row is a test case that the computer checks for you.