作为测试的一部分,我想断言函数返回一个包含正确内容的向量.因此,我将预期数据作为静态变量提供.然而,我找不到一种合适的方法来比较托管向量和静态向量变量的内容.
#[test]
fn test_my_data_matches_expected_data () {
static expected_data: [u8, ..3] = [1, 2, 3];
let my_data: ~[u8] = ~[1, 2, 3]; // actually returned by the function to test
// This would be obvious, but fails:
// -> mismatched types: expected `~[u8]` but found `[u8 * 3]`
assert_eq!(my_data, expected_data);
// Static vectors are told to be available as a borrowed pointer,
// so I tried to borrow a pointer from my_data and compare it:
// -> mismatched types: expected `&const ~[u8]` but found `[u8 * 3]`
assert_eq!(&my_data, expected_data);
// Dereferencing also doesn't work:
// -> type ~[u8] cannot be dereferenced
assert_eq!(*my_data, expected_data);
// Copying the static vector to a managed one works, but this
// involves creating a copy of the data and actually defeats
// the reason to declare it statically:
assert_eq!(my_data, expected_data.to_owned());
}
Update:在比较静态向量之前为其指定一个引用可以解决这个问题,因此我最终使用了一个小宏来断言向量的相等性:
macro_rules! assert_typed_eq (($T: ty, $given: expr, $expected: expr) => ({
let given_val: &$T = $given;
let expected_val: &$T = $expected;
assert_eq!(given_val, expected_val);
}))
用法:assert_typed_eq([u8], my_data, expected_data);