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|
package lru_test
import (
"slices"
"testing"
"codeberg.org/lindenii/furgit/internal/cache/lru"
)
type testValue struct {
weight int64
label string
}
func weightFn(key string, value testValue) int64 {
return value.weight
}
func TestCacheEvictsLRUAndGetUpdatesRecency(t *testing.T) {
t.Parallel()
cache := lru.New[string, testValue](8, weightFn, nil)
cache.Add("a", testValue{weight: 4, label: "a"})
cache.Add("b", testValue{weight: 4, label: "b"})
cache.Add("c", testValue{weight: 4, label: "c"})
if _, ok := cache.Peek("a"); ok {
t.Fatalf("expected a to be evicted")
}
if _, ok := cache.Peek("b"); !ok {
t.Fatalf("expected b to be present")
}
if _, ok := cache.Peek("c"); !ok {
t.Fatalf("expected c to be present")
}
if _, ok := cache.Get("b"); !ok {
t.Fatalf("Get(b) should hit")
}
cache.Add("d", testValue{weight: 4, label: "d"})
if _, ok := cache.Peek("c"); ok {
t.Fatalf("expected c to be evicted after b was touched")
}
if _, ok := cache.Peek("b"); !ok {
t.Fatalf("expected b to remain present")
}
if _, ok := cache.Peek("d"); !ok {
t.Fatalf("expected d to be present")
}
}
func TestCachePeekDoesNotUpdateRecency(t *testing.T) {
t.Parallel()
cache := lru.New[string, testValue](4, weightFn, nil)
cache.Add("a", testValue{weight: 2, label: "a"})
cache.Add("b", testValue{weight: 2, label: "b"})
if _, ok := cache.Peek("a"); !ok {
t.Fatalf("Peek(a) should hit")
}
cache.Add("c", testValue{weight: 2, label: "c"})
if _, ok := cache.Peek("a"); ok {
t.Fatalf("expected a to be evicted; Peek must not update recency")
}
if _, ok := cache.Peek("b"); !ok {
t.Fatalf("expected b to remain present")
}
}
func TestCacheReplaceAndResize(t *testing.T) {
t.Parallel()
var evicted []string
cache := lru.New[string, testValue](10, weightFn, func(key string, value testValue) {
evicted = append(evicted, key+":"+value.label)
})
cache.Add("a", testValue{weight: 4, label: "old"})
cache.Add("b", testValue{weight: 4, label: "b"})
cache.Add("a", testValue{weight: 6, label: "new"})
if cache.Weight() != 10 {
t.Fatalf("Weight() = %d, want 10", cache.Weight())
}
if got, ok := cache.Peek("a"); !ok || got.label != "new" {
t.Fatalf("Peek(a) = (%+v,%v), want new,true", got, ok)
}
if !slices.Equal(evicted, []string{"a:old"}) {
t.Fatalf("evicted = %v, want [a:old]", evicted)
}
cache.SetMaxWeight(8)
if _, ok := cache.Peek("b"); ok {
t.Fatalf("expected b to be evicted after shrinking max weight")
}
if !slices.Equal(evicted, []string{"a:old", "b:b"}) {
t.Fatalf("evicted = %v, want [a:old b:b]", evicted)
}
}
func TestCacheRejectsOversizedWithoutMutation(t *testing.T) {
t.Parallel()
var evicted []string
cache := lru.New[string, testValue](5, weightFn, func(key string, value testValue) {
evicted = append(evicted, key)
})
cache.Add("a", testValue{weight: 3, label: "a"})
if ok := cache.Add("b", testValue{weight: 6, label: "b"}); ok {
t.Fatalf("Add oversized should return false")
}
if got, ok := cache.Peek("a"); !ok || got.label != "a" {
t.Fatalf("cache should remain unchanged after oversized add")
}
if cache.Weight() != 3 {
t.Fatalf("Weight() = %d, want 3", cache.Weight())
}
if len(evicted) != 0 {
t.Fatalf("evicted = %v, want none", evicted)
}
if ok := cache.Add("a", testValue{weight: 6, label: "new"}); ok {
t.Fatalf("oversized replace should return false")
}
if got, ok := cache.Peek("a"); !ok || got.label != "a" {
t.Fatalf("existing key should remain unchanged after oversized replace")
}
if len(evicted) != 0 {
t.Fatalf("evicted = %v, want none", evicted)
}
}
func TestCacheRemoveAndClear(t *testing.T) {
t.Parallel()
var evicted []string
cache := lru.New[string, testValue](10, weightFn, func(key string, value testValue) {
evicted = append(evicted, key)
})
cache.Add("a", testValue{weight: 2, label: "a"})
cache.Add("b", testValue{weight: 3, label: "b"})
cache.Add("c", testValue{weight: 4, label: "c"})
removed, ok := cache.Remove("b")
if !ok || removed.label != "b" {
t.Fatalf("Remove(b) = (%+v,%v), want b,true", removed, ok)
}
if cache.Len() != 2 || cache.Weight() != 6 {
t.Fatalf("post-remove Len/Weight = %d/%d, want 2/6", cache.Len(), cache.Weight())
}
cache.Clear()
if cache.Len() != 0 || cache.Weight() != 0 {
t.Fatalf("post-clear Len/Weight = %d/%d, want 0/0", cache.Len(), cache.Weight())
}
// Remove emits b, then Clear emits oldest-to-newest among remaining: a, c.
if !slices.Equal(evicted, []string{"b", "a", "c"}) {
t.Fatalf("evicted = %v, want [b a c]", evicted)
}
}
func TestCachePanicsForInvalidConfiguration(t *testing.T) {
t.Parallel()
t.Run("negative max", func(t *testing.T) {
defer func() {
if recover() == nil {
t.Fatalf("expected panic")
}
}()
_ = lru.New[string, testValue](-1, weightFn, nil)
})
t.Run("nil weight function", func(t *testing.T) {
defer func() {
if recover() == nil {
t.Fatalf("expected panic")
}
}()
_ = lru.New[string, testValue](1, nil, nil)
})
t.Run("negative entry weight", func(t *testing.T) {
cache := lru.New[string, testValue](10, func(_ string, _ testValue) int64 {
return -1
}, nil)
defer func() {
if recover() == nil {
t.Fatalf("expected panic")
}
}()
cache.Add("x", testValue{weight: 1, label: "x"})
})
t.Run("set negative max", func(t *testing.T) {
cache := lru.New[string, testValue](10, weightFn, nil)
defer func() {
if recover() == nil {
t.Fatalf("expected panic")
}
}()
cache.SetMaxWeight(-1)
})
}
|
