tests: Add unit-tests for file backed storage

Signed-off-by: Alexander Kurbatov <sir.alkurbatov@yandex.ru>

internal/storage/file_backed_test.go

@@ -0,0 +1,93 @@
+package storage_test
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/alkurbatov/metrics-collector/internal/storage"
+	"github.com/alkurbatov/metrics-collector/pkg/metrics"
+	"github.com/stretchr/testify/require"
+)
+
+func createStoreWithData(
+	t *testing.T,
+	storePath string,
+	syncMode bool,
+) *storage.FileBackedStorage {
+	t.Helper()
+
+	ctx := context.Background()
+	store := storage.NewFileBackedStorage(storePath, syncMode)
+
+	batch := map[string]storage.Record{
+		"PollCount_counter": {Name: "PollCount", Value: metrics.Counter(10)},
+		"Alloc_gauge":       {Name: "Alloc", Value: metrics.Gauge(11.356)},
+	}
+	err := store.PushBatch(ctx, batch)
+	require.NoError(t, err)
+
+	err = store.Push(
+		ctx,
+		"HeapSys_gauge",
+		storage.Record{Name: "HeapSys", Value: metrics.Gauge(7831552)},
+	)
+	require.NoError(t, err)
+
+	err = store.Push(
+		ctx,
+		"RequestsCount_counter",
+		storage.Record{Name: "RequestsCount", Value: metrics.Counter(1)},
+	)
+	require.NoError(t, err)
+
+	return store
+}
+
+func TestSyncDumpRestoreStorage(t *testing.T) {
+	storePath := "/tmp/test-sync-dump-restore.json"
+
+	t.Cleanup(func() {
+		err := os.Remove(storePath)
+		require.NoError(t, err)
+	})
+
+	store := createStoreWithData(t, storePath, true)
+	storedData := store.Snapshot()
+
+	store = storage.NewFileBackedStorage(storePath, true)
+	err := store.Restore()
+	require.NoError(t, err)
+
+	restoredData := store.Snapshot()
+	require.Equal(t, storedData, restoredData)
+}
+
+func TestAsyncDumpRestoreStorage(t *testing.T) {
+	storePath := "/tmp/test-async-dump-restore.json"
+
+	t.Cleanup(func() {
+		err := os.Remove(storePath)
+		require.NoError(t, err)
+	})
+
+	store := createStoreWithData(t, storePath, false)
+	storedData := store.Snapshot()
+
+	err := store.Close(context.Background())
+	require.NoError(t, err)
+
+	store = storage.NewFileBackedStorage(storePath, false)
+	err = store.Restore()
+	require.NoError(t, err)
+
+	restoredData := store.Snapshot()
+	require.Equal(t, storedData, restoredData)
+}
+
+func TestRestoreDoesntFailIfNoSourceFile(t *testing.T) {
+	store := storage.NewFileBackedStorage("xxx", false)
+
+	err := store.Restore()
+	require.NoError(t, err)
+}