---

yaml
---
r: 29756
b: refs/heads/incoming
c: ac4132b
h: refs/heads/master
v: v3

Author: brson

[refs]

@@ -6,7 +6,7 @@ refs/heads/try: d324a424d8f84b1eb049b12cf34182bda91b0024
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: d0c6ce338884ee21843f4b40bf6bf18d222ce5df
-refs/heads/incoming: 78d19d8f1bdb64317ebdb072c25ee1240a562095
+refs/heads/incoming: ac4132b7fda1e2bd356a5af8d89badf3e05f7a1a
 refs/heads/dist-snap: 2f32a1581f522e524009138b33b1c7049ced668d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/incoming/src/libstd/cell.rs

@@ -18,17 +18,18 @@ fn empty_cell<T>() -> Cell<T> {
 impl<T> Cell<T> {
     /// Yields the value, failing if the cell is empty.
     fn take() -> T {
-        let mut value = none;
-        value <-> self.value;
-        if value.is_none() {
+        if self.is_empty() {
             fail ~"attempt to take an empty cell";
         }
+
+        let mut value = none;
+        value <-> self.value;
         return option::unwrap(value);
     }
 
     /// Returns the value, failing if the cell is full.
     fn put_back(+value: T) {
-        if self.value.is_none() {
+        if !self.is_empty() {
             fail ~"attempt to put a value back into a full cell";
         }
         self.value = some(move value);
@@ -39,3 +40,30 @@ impl<T> Cell<T> {
         self.value.is_none()
     }
 }
+
+#[test]
+fn test_basic() {
+    let value_cell = Cell(~10);
+    assert !value_cell.is_empty();
+    let value = value_cell.take();
+    assert value == ~10;
+    assert value_cell.is_empty();
+    value_cell.put_back(value);
+    assert !value_cell.is_empty();
+}
+
+#[test]
+#[should_fail]
+#[ignore(cfg(windows))]
+fn test_take_empty() {
+    let value_cell = empty_cell::<~int>();
+    value_cell.take();
+}
+
+#[test]
+#[should_fail]
+#[ignore(cfg(windows))]
+fn test_put_back_non_empty() {
+    let value_cell = Cell(~10);
+    value_cell.put_back(~20);
+}