---

yaml
---
r: 20766
b: refs/heads/snap-stage3
c: a89ed49
h: refs/heads/master
v: v3

Author: bblum

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: e430a699f2c60890d9b86069fd0c68a70ece7120
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: 513557b465a6393aebf8d309320c7eaab9ceae2c
+refs/heads/snap-stage3: a89ed49d3d01abbd49889832d87650b6c99ff85c
 refs/heads/try: ffbe0e0e00374358b789b0037bcb3a577cd218be
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b

branches/snap-stage3/src/libcore/hash.rs

@@ -401,3 +401,45 @@ fn test_hash_uint() {
     assert hash_u64(val as u64) != hash_uint(val as uint);
     assert hash_u32(val as u32) == hash_uint(val as uint);
 }
+
+#[test]
+fn test_hash_idempotent() {
+    let val64 = 0xdeadbeef_deadbeef_u64;
+    assert hash_u64(val64) == hash_u64(val64);
+    let val32 = 0xdeadbeef_u32;
+    assert hash_u32(val32) == hash_u32(val32);
+}
+
+#[test]
+fn test_hash_no_bytes_dropped_64() {
+    let val = 0xdeadbeef_deadbeef_u64;
+
+    assert hash_u64(val) != hash_u64(zero_byte(val, 0));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 1));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 2));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 3));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 4));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 5));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 6));
+    assert hash_u64(val) != hash_u64(zero_byte(val, 7));
+
+    fn zero_byte(val: u64, byte: uint) -> u64 {
+        assert 0 <= byte; assert byte < 8;
+        val & !(0xff << (byte * 8))
+    }
+}
+
+#[test]
+fn test_hash_no_bytes_dropped_32() {
+    let val = 0xdeadbeef_u32;
+
+    assert hash_u32(val) != hash_u32(zero_byte(val, 0));
+    assert hash_u32(val) != hash_u32(zero_byte(val, 1));
+    assert hash_u32(val) != hash_u32(zero_byte(val, 2));
+    assert hash_u32(val) != hash_u32(zero_byte(val, 3));
+
+    fn zero_byte(val: u32, byte: uint) -> u32 {
+        assert 0 <= byte; assert byte < 4;
+        val & !(0xff << (byte * 8))
+    }
+}