---

yaml
---
r: 162287
b: refs/heads/auto
c: a20926a
h: refs/heads/master
i:
  162285: 6df48d9
  162283: c0c8f78
  162279: be9a612
  162271: b3f070d
v: v3

Author: sfackler

[refs]

@@ -10,7 +10,7 @@ refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 3246d4f36979658c61c9e2bcfe524b1d45b3257a
+refs/heads/auto: a20926a51add66ab67053843e244efb1a4d7ad76
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336

branches/auto/src/doc/guide-testing.md

@@ -89,6 +89,21 @@ fn test_out_of_bounds_failure() {
 }
 ~~~
 
+`#[should_fail]` tests can be fragile as it's hard to guarantee that the test
+didn't fail for an unexpected reason. To help with this, an optional `expected`
+parameter can be added to the `should_fail` attribute. The test harness will
+make sure that the failure message contains the provided text. A safer version
+of the example above would be:
+
+~~~test_harness
+#[test]
+#[should_fail(expected = "index out of bounds")]
+fn test_out_of_bounds_failure() {
+    let v: &[int] = &[];
+    v[0];
+}
+~~~
+
 A test runner built with the `--test` flag supports a limited set of
 arguments to control which tests are run: