lru_cache_test.go

package ldclient

import (
  "testing"

  "github.com/stretchr/testify/assert"
)

func TestLRUCache(t *testing.T) {
  t.Run("add returns false for never-seen value", func(t *testing.T) {
    cache := newLruCache(10)
    assert.False(t, cache.add("a"))
  })

  t.Run("add returns true for already-seen value", func(t *testing.T) {
    cache := newLruCache(10)
    cache.add("a")
    assert.True(t, cache.add("a"))
  })

  t.Run("oldest value is discarded when capacity is exceeded", func(t *testing.T) {
    cache := newLruCache(2)
    cache.add("a")
    cache.add("b")
    cache.add("c")
    assert.True(t, cache.add("c"))
    assert.True(t, cache.add("b"))
    assert.False(t, cache.add("a"))
  })

  t.Run("re-adding an existing value makes it new again", func(t *testing.T) {
    cache := newLruCache(2)
    cache.add("a")
    cache.add("b")
    cache.add("a")
    cache.add("c")
    assert.True(t, cache.add("c"))
    assert.True(t, cache.add("a"))
    assert.False(t, cache.add("b"))
  })

  t.Run("zero-length cache treats values as new", func(t *testing.T) {
    cache := newLruCache(0)
    assert.False(t, cache.add("a"))
    assert.False(t, cache.add("a"))
  })
}