completed test part

solutions/17_tests/tests2.rs

@@ -1,4 +1,22 @@
-fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+// Calculates the power of 2 using a bit shift.
+// `1 << n` is equivalent to "2 to the power of n".
+fn power_of_2(n: u8) -> u64 {
+    1 << n
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn you_can_assert_eq() {
+        assert_eq!(power_of_2(0), 1);
+        assert_eq!(power_of_2(1), 2);
+        assert_eq!(power_of_2(2), 4);
+        assert_eq!(power_of_2(3), 8);
+    }
 }