Closures and Cacher object

[learn-rust.git] / tests / test_lib.rs

diff --git a/tests/test_lib.rs b/tests/test_lib.rs
index 44d7f87cee54405631e9412ced6542eec01eaed6..186ffd7dcf3756d8262f9aefdd6bfb0ff192525b 100644 (file)
--- a/tests/test_lib.rs
+++ b/tests/test_lib.rs
@@ -6,3 +6,46 @@ fn test_longest() {
     assert_eq!(longest("abc", "def"), "def");
     assert_eq!(longest("abc", "defg"), "defg");
 }
+
+// FIXME: How to make this not unsafe?
+static mut CALLED: u32 = 0;
+
+#[test]
+fn test_cacher_int_int() {
+    unsafe { CALLED = 0; }
+    let mut cacher = Cacher::new(|x| {
+        unsafe { CALLED += 1; }
+        2 * x
+    });
+    assert_eq!(cacher.value(1), 2);
+    unsafe { assert_eq!(CALLED, 1); }
+    // second time cached
+    assert_eq!(cacher.value(1), 2);
+    unsafe { assert_eq!(CALLED, 1); }
+    // re-evaluated for new value
+    assert_eq!(cacher.value(-2), -4);
+    unsafe { assert_eq!(CALLED, 2); }
+    // old arg still cached
+    assert_eq!(cacher.value(1), 2);
+    unsafe { assert_eq!(CALLED, 2); }
+}
+
+#[test]
+fn test_cacher_str_usize() {
+    unsafe { CALLED = 0; }
+    let mut cacher = Cacher::new(|x: &str| {
+        unsafe { CALLED += 1; }
+        x.len()
+    });
+    assert_eq!(cacher.value("abc"), 3);
+    unsafe { assert_eq!(CALLED, 1); }
+    // second time cached
+    assert_eq!(cacher.value("abc"), 3);
+    unsafe { assert_eq!(CALLED, 1); }
+    // re-evaluated for new value
+    assert_eq!(cacher.value("defg"), 4);
+    unsafe { assert_eq!(CALLED, 2); }
+    // old arg still cached
+    assert_eq!(cacher.value("abc"), 3);
+    unsafe { assert_eq!(CALLED, 2); }
+}