Recreate blob cache if missing (closes #104)

cache_test.go

@@ -0,0 +1,45 @@
+package restic_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/restic/restic"
+	"github.com/restic/restic/backend"
+)
+
+func TestCache(t *testing.T) {
+	be := setupBackend(t)
+	defer teardownBackend(t, be)
+	key := setupKey(t, be, "geheim")
+	server := restic.NewServerWithKey(be, key)
+
+	cache, err := restic.NewCache(server)
+	ok(t, err)
+
+	arch, err := restic.NewArchiver(server)
+	ok(t, err)
+
+	// archive some files, this should automatically cache all blobs from the snapshot
+	_, id, err := arch.Snapshot(nil, []string{*benchArchiveDirectory}, nil)
+
+	// try to load map from cache
+	rd, err := cache.Load(backend.Snapshot, "blobs", id)
+	ok(t, err)
+
+	dec := json.NewDecoder(rd)
+
+	m := &restic.Map{}
+	err = dec.Decode(m)
+	ok(t, err)
+
+	// remove cached blob list
+	ok(t, cache.Purge(backend.Snapshot, "blobs", id))
+
+	// recreate cached blob list
+	m2, err := restic.CacheSnapshotBlobs(server, cache, id)
+	ok(t, err)
+
+	// compare maps
+	assert(t, m.Equals(m2), "Maps are not equal")
+}