From 90de3ab4e61db4db6c1616f0fd77e31fddad5edf Mon Sep 17 00:00:00 2001
From: Dmitry Verkhoturov <paskal.07@gmail.com>
Date: Tue, 22 Aug 2023 10:16:32 +0200
Subject: [PATCH] add evict behaviour tests

---
 expirable/expirable_lru_test.go | 37 +++++++++++++++++++++++++++++
 lru_test.go                     | 37 +++++++++++++++++++++++++++++
 simplelru/lru_test.go           | 41 ++++++++++++++++++++++++++++++++-
 3 files changed, 114 insertions(+), 1 deletion(-)

diff --git a/expirable/expirable_lru_test.go b/expirable/expirable_lru_test.go
index cc328e3..a7dd6bb 100644
--- a/expirable/expirable_lru_test.go
+++ b/expirable/expirable_lru_test.go
@@ -478,6 +478,43 @@ func TestLRURemoveOldest(t *testing.T) {
 	}
 }
 
+// https://github.com/hashicorp/golang-lru/issues/141
+// test highlighting behaviour of eviction of the key with changed value
+func TestCache_EvictionSameKey(t *testing.T) {
+	var evictedKeys []int
+
+	cache := NewLRU[int, struct{}](
+		2,
+		func(key int, _ struct{}) {
+			evictedKeys = append(evictedKeys, key)
+		},
+		0)
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(2, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 2}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{2, 1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(3, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 3}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	if !reflect.DeepEqual(evictedKeys, []int{2}) {
+		t.Fatalf("evictedKeys differs from expected: %v", evictedKeys)
+	}
+}
+
 func ExampleLRU() {
 	// make cache with 10ms TTL and 5 max keys
 	cache := NewLRU[string, string](5, nil, time.Millisecond*10)
diff --git a/lru_test.go b/lru_test.go
index 9da0b23..2ca8d88 100644
--- a/lru_test.go
+++ b/lru_test.go
@@ -4,6 +4,7 @@
 package lru
 
 import (
+	"reflect"
 	"testing"
 )
 
@@ -293,3 +294,39 @@ func TestLRUResize(t *testing.T) {
 		t.Errorf("Cache should have contained 2 elements")
 	}
 }
+
+// https://github.com/hashicorp/golang-lru/issues/141
+// test highlighting behaviour of eviction of the key with changed value
+func TestCache_EvictionSameKey(t *testing.T) {
+	var evictedKeys []int
+
+	cache, _ := NewWithEvict(
+		2,
+		func(key int, _ struct{}) {
+			evictedKeys = append(evictedKeys, key)
+		})
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(2, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 2}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{2, 1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(3, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 3}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	if !reflect.DeepEqual(evictedKeys, []int{1}) {
+		t.Fatalf("evictedKeys differs from expected: %v", evictedKeys)
+	}
+}
diff --git a/simplelru/lru_test.go b/simplelru/lru_test.go
index a6b247f..f22050c 100644
--- a/simplelru/lru_test.go
+++ b/simplelru/lru_test.go
@@ -3,7 +3,10 @@
 
 package simplelru
 
-import "testing"
+import (
+	"reflect"
+	"testing"
+)
 
 func TestLRU(t *testing.T) {
 	evictCounter := 0
@@ -207,3 +210,39 @@ func TestLRU_Resize(t *testing.T) {
 		t.Errorf("Cache should have contained 2 elements")
 	}
 }
+
+// https://github.com/hashicorp/golang-lru/issues/141
+// test highlighting behaviour of eviction of the key with changed value
+func TestCache_EvictionSameKey(t *testing.T) {
+	var evictedKeys []int
+
+	cache, _ := NewLRU(
+		2,
+		func(key int, _ struct{}) {
+			evictedKeys = append(evictedKeys, key)
+		})
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(2, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 2}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(1, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{2, 1}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	cache.Add(3, struct{}{})
+	if !reflect.DeepEqual(cache.Keys(), []int{1, 3}) {
+		t.Fatalf("keys differs from expected: %v", cache.Keys())
+	}
+
+	if !reflect.DeepEqual(evictedKeys, []int{1, 2}) {
+		t.Fatalf("evictedKeys differs from expected: %v", evictedKeys)
+	}
+}