[#1686] local_object_storage: Add generic tests

Use them for writecache as a simple example.

Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>

pkg/local_object_storage/writecache/generic_test.go

@@ -0,0 +1,29 @@
+package writecache
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"testing"
+
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/internal/storagetest"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zaptest"
+)
+
+func TestGeneric(t *testing.T) {
+	defer func() { _ = os.RemoveAll(t.Name()) }()
+
+	var n int
+	newCache := func(t *testing.T) storagetest.Component {
+		n++
+		dir := filepath.Join(t.Name(), strconv.Itoa(n))
+		require.NoError(t, os.MkdirAll(dir, os.ModePerm))
+		return New(
+			WithLogger(zaptest.NewLogger(t)),
+			WithFlushWorkersCount(2),
+			WithPath(dir))
+	}
+
+	storagetest.TestAll(t, newCache)
+}