initial commit

exercises/02_basic_calculator/04_panics/Cargo.toml

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+[package]
+name = "panics"
+version = "0.1.0"
+edition = "2021"
+
+[lints.rust]
+# We silence dead code warnings for the time being in order to reduce
+# compiler noise.
+# We'll re-enable them again once we explain how visibility works in Rust.
+dead_code = "allow"

exercises/02_basic_calculator/04_panics/src/lib.rs

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+/// Given the start and end points of a journey, and the time it took to complete the journey,
+/// calculate the average speed of the journey.
+fn speed(start: u32, end: u32, time_elapsed: u32) -> u32 {
+    // TODO: Panic with a custom message if `time_elapsed` is 0
+
+    (end - start) / time_elapsed
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::speed;
+
+    #[test]
+    fn case1() {
+        assert_eq!(speed(0, 10, 10), 1);
+    }
+
+    #[test]
+    // 👇 With the `#[should_panic]` annotation we can assert that we expect the code
+    //    under test to panic. We can also check the panic message by using `expected`.
+    //    This is all part of Rust's built-in test framework!
+    #[should_panic(expected = "The journey took no time at all. That's impossible!")]
+    fn by_zero() {
+        speed(0, 10, 0);
+    }
+}