add LRU Cache

lru/lru_test.go

@@ -0,0 +1,35 @@
+package lru_test
+
+import (
+	"testing"
+
+	"github.com/cubixle/lru"
+)
+
+func TestCache(t *testing.T) {
+	cache := lru.NewCache(2)
+	cache.Set("usa", "washington")
+	cache.Set("uk", "london")
+
+	city := cache.Get("usa")
+	if city != "washington" {
+		t.Fatal("didn't get the correct city for usa")
+	}
+
+	city = cache.Get("uk")
+	if city != "london" {
+		t.Fatal("didn't get the correct city for uk")
+	}
+
+	cache.Set("france", "paris")
+
+	city = cache.Get("france")
+	if city != "paris" {
+		t.Fatal("didn't get the correct city for uk")
+	}
+
+	city = cache.Get("usa")
+	if city != "" {
+		t.Fatal("usa is still in the cache but should have been removed")
+	}
+}