Rustlings solution | tests

// tests1.rs
// Tests are important to ensure that your code does what you think it should do.
// Tests can be run on this file with the following command:
// rustlings run tests1

// This test has a problem with it -- make the test compile! Make the test
// pass! Make the test fail!
// Execute `rustlings hint tests1` or use the `hint` watch subcommand for a hint.

#[cfg(test)]
mod tests {
    #[test]
    fn you_can_assert() {
        assert!(true);
    }
}

// tests2.rs
// This test has a problem with it -- make the test compile! Make the test
// pass! Make the test fail!
// Execute `rustlings hint tests2` or use the `hint` watch subcommand for a hint.

#[cfg(test)]
mod tests {
    #[test]
    fn you_can_assert_eq() {
        assert_eq!(1, 1);
    }
}

// tests3.rs
// This test isn't testing our function -- make it do that in such a way that
// the test passes. Then write a second test that tests whether we get the result
// we expect to get when we call `is_even(5)`.
// Execute `rustlings hint tests3` or use the `hint` watch subcommand for a hint.

pub fn is_even(num: i32) -> bool {
    num % 2 == 0
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn is_true_when_even() {
        assert!(true == is_even(4));
    }

    #[test]
    fn is_false_when_odd() {
        assert!(false == is_even(5));
    }
}

// tests4.rs
//
// Make sure that we're testing for the correct conditions!
//
// Execute `rustlings hint tests4` or use the `hint` watch subcommand for a
// hint.

struct Rectangle {
    width: i32,
    height: i32
}

impl Rectangle {
    // Only change the test functions themselves
    pub fn new(width: i32, height: i32) -> Self {
        if width <= 0 || height <= 0 {
            panic!("Rectangle width and height cannot be negative!")
        }
        Rectangle {width, height}
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn correct_width_and_height() {
        // This test should check if the rectangle is the size that we pass into its constructor
        let rect = Rectangle::new(10, 20);
        assert_eq!(rect.width, 10); // check width
        assert_eq!(rect.height, 20); // check height
    }

    #[test]
    #[should_panic(expected = "Rectangle width and height cannot be negative!")]
    fn negative_width() {
        // This test should check if program panics when we try to create rectangle with negative width
        let _rect = Rectangle::new(-10, 10);
    }

    #[test]
    #[should_panic(expected = "Rectangle width and height cannot be negative!")]
    fn negative_height() {
        // This test should check if program panics when we try to create rectangle with negative height
        let _rect = Rectangle::new(10, -10);
    }
}