feat: Add fizzbuzz.rs exercise

exercises/fizzbuzz.rs

@@ -0,0 +1,49 @@
+// fizzbuzz challenge
+
+// Make a simple code which fulfills the given tests
+// Starting code is already given to you :)
+
+/* Write a program that substitues the following:
+ * mulitples of 3 => "fizz"
+ * multiples of 5 => "buzz"
+ * mulitples of 3 and 5 => "fizzbuzz"
+ */
+
+// I AM NOT DONE
+
+pub fn fizzbuzz(num: i32) -> String {
+	match (num % 3, num % 5) {
+		(0, 0) => "fizzbuzz".to_string(),
+		(0, _) => "fizz".to_string(),
+		(_, 0) => "buzz".to_string(),
+		(_, _) => num.to_string(),
+	}
+}
+
+// Don't change this part(the tests)
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn fizz() {
+		assert_eq!(fizzbuzz(3), "fizz".to_string());
+		assert_eq!(fizzbuzz(6), "fizz".to_string());
+		assert_eq!(fizzbuzz(53), "53".to_string());
+	}
+
+	#[test]
+	fn buzz() {
+		assert_eq!(fizzbuzz(5), "buzz".to_string());
+		assert_eq!(fizzbuzz(10), "buzz".to_string());
+		assert_eq!(fizzbuzz(13), "13".to_string());
+	}
+
+	#[test]
+	fn fizz_and_buzz() {
+		assert_eq!(fizzbuzz(15), "fizzbuzz".to_string());
+		assert_eq!(fizzbuzz(45), "fizzbuzz".to_string());
+		assert_eq!(fizzbuzz(31), "31".to_string());
+	}
+}