Use a macro in test_decode_utf8 to preserve line numbers in panic messages.

Author: SimonSapin

src/libcoretest/char.rs

@@ -358,29 +358,31 @@ fn eu_iterator_specializations() {
 
 #[test]
 fn test_decode_utf8() {
-    use core::char::*;
-    use core::iter::FromIterator;
-
-    for &(str, bs) in [("", &[] as &[u8]),
-                       ("A", &[0x41u8] as &[u8]),
-                       ("�", &[0xC1u8, 0x81u8] as &[u8]),
-                       ("♥", &[0xE2u8, 0x99u8, 0xA5u8]),
-                       ("♥A", &[0xE2u8, 0x99u8, 0xA5u8, 0x41u8] as &[u8]),
-                       ("�", &[0xE2u8, 0x99u8] as &[u8]),
-                       ("�A", &[0xE2u8, 0x99u8, 0x41u8] as &[u8]),
-                       ("�", &[0xC0u8] as &[u8]),
-                       ("�A", &[0xC0u8, 0x41u8] as &[u8]),
-                       ("�", &[0x80u8] as &[u8]),
-                       ("�A", &[0x80u8, 0x41u8] as &[u8]),
-                       ("�", &[0xFEu8] as &[u8]),
-                       ("�A", &[0xFEu8, 0x41u8] as &[u8]),
-                       ("�", &[0xFFu8] as &[u8]),
-                       ("�A", &[0xFFu8, 0x41u8] as &[u8])].into_iter() {
-        assert!(Iterator::eq(str.chars(),
-                             decode_utf8(bs.into_iter().map(|&b|b))
-                                 .map(|r_b| r_b.unwrap_or('\u{FFFD}'))),
-                "chars = {}, bytes = {:?}, decoded = {:?}", str, bs,
-                Vec::from_iter(decode_utf8(bs.into_iter().map(|&b|b))
-                                   .map(|r_b| r_b.unwrap_or('\u{FFFD}'))));
+    macro_rules! assert_decode_utf8 {
+        ($input_bytes: expr, $expected_str: expr) => {
+            let input_bytes: &[u8] = &$input_bytes;
+            let s = char::decode_utf8(input_bytes.iter().cloned())
+                .map(|r_b| r_b.unwrap_or('\u{FFFD}'))
+                .collect::<String>();
+            assert_eq!(s, $expected_str,
+                       "input bytes: {:?}, expected str: {:?}, result: {:?}",
+                       input_bytes, $expected_str, s);
+        }
     }
+
+    assert_decode_utf8!([], "");
+    assert_decode_utf8!([0x41], "A");
+    assert_decode_utf8!([0xC1, 0x81], "�");
+    assert_decode_utf8!([0xE2, 0x99, 0xA5], "♥");
+    assert_decode_utf8!([0xE2, 0x99, 0xA5, 0x41], "♥A");
+    assert_decode_utf8!([0xE2, 0x99], "�");
+    assert_decode_utf8!([0xE2, 0x99, 0x41], "�A");
+    assert_decode_utf8!([0xC0], "�");
+    assert_decode_utf8!([0xC0, 0x41], "�A");
+    assert_decode_utf8!([0x80], "�");
+    assert_decode_utf8!([0x80, 0x41], "�A");
+    assert_decode_utf8!([0xFE], "�");
+    assert_decode_utf8!([0xFE, 0x41], "�A");
+    assert_decode_utf8!([0xFF], "�");
+    assert_decode_utf8!([0xFF, 0x41], "�A");
 }