1const expect = @import("std").testing.expect;
 2
 3fn fibonacci(index: u32) u32 {
 4    //if (index < 2) return index;
 5    return fibonacci(index - 1) + fibonacci(index - 2);
 6}
 7
 8test "fibonacci" {
 9    try comptime expect(fibonacci(7) == 13);
10}
11
12// test_error=overflow of integer type