[#236] api: Refactor caches: ObjectsList, Objects

Move ObjectsList from layer to cache package
Rename object_cache.go to objects.go

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

api/layer/object_test.go

@@ -0,0 +1,114 @@
+package layer
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-s3-gw/api"
+	"github.com/stretchr/testify/require"
+)
+
+func randID(t *testing.T) *object.ID {
+	id := object.NewID()
+	id.SetSHA256(randSHA256Checksum(t))
+
+	return id
+}
+
+func randSHA256Checksum(t *testing.T) (cs [sha256.Size]byte) {
+	_, err := rand.Read(cs[:])
+	require.NoError(t, err)
+
+	return
+}
+
+func TestTrimAfterObjectName(t *testing.T) {
+	var (
+		objects []*api.ObjectInfo
+		names   = []string{"b", "c", "d"}
+	)
+	for _, name := range names {
+		objects = append(objects, &api.ObjectInfo{Name: name})
+	}
+
+	t.Run("startafter before all objects", func(t *testing.T) {
+		actual := trimAfterObjectName("a", objects)
+		require.Equal(t, objects, actual)
+	})
+
+	t.Run("startafter first object", func(t *testing.T) {
+		actual := trimAfterObjectName(names[0], objects)
+		require.Equal(t, objects[1:], actual)
+	})
+
+	t.Run("startafter second-to-last object", func(t *testing.T) {
+		actual := trimAfterObjectName(names[len(names)-2], objects)
+		require.Equal(t, objects[len(objects)-1:], actual)
+	})
+
+	t.Run("startafter last object", func(t *testing.T) {
+		actual := trimAfterObjectName(names[len(names)-1], objects)
+		require.Empty(t, actual)
+	})
+
+	t.Run("startafter after all objects", func(t *testing.T) {
+		actual := trimAfterObjectName("z", objects)
+		require.Nil(t, actual)
+	})
+
+	t.Run("empty objects", func(t *testing.T) {
+		actual := trimAfterObjectName(names[0], []*api.ObjectInfo{})
+		require.Nil(t, actual)
+	})
+
+	t.Run("nil objects", func(t *testing.T) {
+		actual := trimAfterObjectName(names[0], nil)
+		require.Nil(t, actual)
+	})
+
+	t.Run("empty startafter", func(t *testing.T) {
+		actual := trimAfterObjectName("", objects)
+		require.Equal(t, objects, actual)
+	})
+}
+
+func TestTrimAfterObjectID(t *testing.T) {
+	var (
+		objects     []*api.ObjectInfo
+		ids         []*object.ID
+		numberOfIDS = 3
+	)
+
+	for i := 0; i < numberOfIDS; i++ {
+		id := randID(t)
+		objects = append(objects, &api.ObjectInfo{ID: id})
+		ids = append(ids, id)
+	}
+
+	t.Run("existing id", func(t *testing.T) {
+		actual := trimAfterObjectID(ids[0].String(), objects)
+		require.Equal(t, objects[1:], actual)
+	})
+
+	t.Run("second to last id", func(t *testing.T) {
+		actual := trimAfterObjectID(ids[len(ids)-2].String(), objects)
+		require.Equal(t, objects[len(objects)-1:], actual)
+	})
+
+	t.Run("non-existing id", func(t *testing.T) {
+		actual := trimAfterObjectID("z", objects)
+		require.Nil(t, actual)
+	})
+
+	t.Run("last id", func(t *testing.T) {
+		actual := trimAfterObjectID(ids[len(ids)-1].String(), objects)
+		require.Empty(t, actual)
+	})
+
+	t.Run("empty id", func(t *testing.T) {
+		actual := trimAfterObjectID("", objects)
+		require.Nil(t, actual)
+	})
+}