Add few test cases to consistenthash and lru packages

consistenthash/consistenthash_test.go

@@ -34,6 +34,12 @@ func TestHashing(t *testing.T) {
  return uint32(i)
  })
 
+ // Get a value before any key is added to the hash
+ // Should yield an empty string
+ if emptyHashValue := hash.Get("empty hash key"); emptyHashValue != "" {
+ t.Errorf("Get on an empty hash = %q; want empty string", emptyHashValue)
+ }
+
  // Given the above hash function, this will give replicas with "hashes":
  // 2, 4, 6, 12, 14, 16, 22, 24, 26
  hash.Add("6", "4", "2")

lru/lru_test.go

@@ -71,3 +71,56 @@ func TestRemove(t *testing.T) {
  t.Fatal("TestRemove returned a removed entry")
  }
 }
+
+func TestAddWithMaxEntries(t *testing.T) {
+ lru := New(3)
+ items := []struct {
+ key string
+ value string
+ shouldExist bool
+ }{
+ {"one", "1", false},
+ {"two", "2", true},
+ {"three", "3", true},
+ {"four", "4", true},
+ {"four", "4", true},
+ }
+ for _, tt := range items {
+ lru.Add(tt.key, tt.value)
+ }
+ if lru.Len() != 3 {
+ t.Fatalf("lru size: %d items; expected: 3 items", lru.Len())
+ }
+ for _, tt := range items {
+ if _, ok := lru.Get(tt.key); ok != tt.shouldExist {
+ t.Fatalf("value exists: %v for key:%s; expected: %v", ok, tt.key, tt.shouldExist)
+ }
+ }
+}
+
+func TestClearedCache(t *testing.T) {
+ lru := New(0)
+
+ // Test clearing out the cache
+ if lru.Clear(); lru.cache != nil && lru.ll != nil {
+ t.Fatalf("lru cache not Cleared")
+ }
+
+ // Test adding to a cache which is cleared
+ if lru.Add("foo", "bar"); lru.Len() != 1 {
+ t.Fatalf("lru size: %d items; expected: 1 item", lru.Len())
+ }
+
+ // Clear the cache
+ lru.Clear()
+
+ // Test Get from a cleared cache
+ if val, ok := lru.Get("foo"); val != nil || ok {
+ t.Fatalf("Get from cleared cache: %v, %v; expected: <nil>, false", val, ok)
+ }
+
+ // Test the length of a cleared cache
+ if length := lru.Len(); length != 0 {
+ t.Fatalf("Len of cleared cache: %d; expected: 0", length)
+ }
+}