Fix eviction check

cache.go

@@ -74,8 +74,8 @@ func (c *cache) Set(k string, x interface{}, d time.Duration) {
 	// adds ~200 ns (as of go1.)
 	c.mu.Unlock()
 
-	// try to call onEvicted if key existed before but it was expired before cleanup
-	if evicted && item.Expired() {
+	// try to call onEvicted if key existed before but the item is different
+	if evicted && item.Object != x {
 		c.onEvicted(k, item.Object)
 	}
 }

cache_test.go

@@ -1265,11 +1265,9 @@ func TestOnEvictedCalledBeforeSet(t *testing.T) {
 		t.Fatal("tc.onEvicted is nil")
 	}
 
-	// ensure item expires
-	time.Sleep(expiry)
-
-	// calling Set again should evict expired item
-	tc.Set("foo", 3, DefaultExpiration)
+	// calling Set again with the same key should evict
+	// the item if different
+	tc.Set("foo", 5, DefaultExpiration)
 
 	x, _ := tc.Get("bar")
 	if !works {