repository: Allow skipping verification for tests

Some tests have to explicitly create pack files with blobs that don't
match their ID. For those blobs the builtin verification of the
repository must be disabled.

internal/repository/repack_test.go

@@ -346,7 +346,8 @@ func TestRepackWrongBlob(t *testing.T) {
 }
 
 func testRepackWrongBlob(t *testing.T, version uint) {
-	repo := repository.TestRepositoryWithVersion(t, version)
+	// disable verification to allow adding corrupted blobs to the repository
+	repo := repository.TestRepositoryWithBackend(t, nil, version, repository.Options{NoVerifyPack: true})
 
 	seed := time.Now().UnixNano()
 	rand.Seed(seed)
@@ -371,7 +372,8 @@ func TestRepackBlobFallback(t *testing.T) {
 }
 
 func testRepackBlobFallback(t *testing.T, version uint) {
-	repo := repository.TestRepositoryWithVersion(t, version)
+	// disable verification to allow adding corrupted blobs to the repository
+	repo := repository.TestRepositoryWithBackend(t, nil, version, repository.Options{NoVerifyPack: true})
 
 	seed := time.Now().UnixNano()
 	rand.Seed(seed)

internal/repository/repository.go

@@ -59,8 +59,9 @@ type Repository struct {
 }
 
 type Options struct {
-	Compression CompressionMode
-	PackSize    uint
+	Compression  CompressionMode
+	PackSize     uint
+	NoVerifyPack bool
 }
 
 // CompressionMode configures if data should be compressed.
@@ -444,6 +445,10 @@ func (r *Repository) saveAndEncrypt(ctx context.Context, t restic.BlobType, data
 }
 
 func (r *Repository) verifyCiphertext(buf []byte, uncompressedLength int, id restic.ID) error {
+	if r.opts.NoVerifyPack {
+		return nil
+	}
+
 	nonce, ciphertext := buf[:r.key.NonceSize()], buf[r.key.NonceSize():]
 	plaintext, err := r.key.Open(nil, nonce, ciphertext, nil)
 	if err != nil {
@@ -539,6 +544,10 @@ func (r *Repository) SaveUnpacked(ctx context.Context, t restic.FileType, buf []
 }
 
 func (r *Repository) verifyUnpacked(buf []byte, t restic.FileType, expected []byte) error {
+	if r.opts.NoVerifyPack {
+		return nil
+	}
+
 	nonce, ciphertext := buf[:r.key.NonceSize()], buf[r.key.NonceSize():]
 	plaintext, err := r.key.Open(nil, nonce, ciphertext, nil)
 	if err != nil {