WIP: cheap scrypt in tests

internal/secret/crypto.go

@@ -28,6 +28,16 @@ var (
 // terminal to read the mnemonic from, reading it failed, or it was empty.
 var ErrMnemonicNotRead = errors.New("failed to read mnemonic")
 
+// ScryptWorkFactor, when not zero, replaces age's scrypt work factor, 18, in
+// EncryptWithPassphrase. It is log2 of the number of scrypt iterations. age's
+// costs about a second and 256 MiB per passphrase, on purpose, as it does each
+// guess at one. Only tests set it, lower, before any test runs, so that the
+// passphrase unlockers they create cost nothing; the program leaves it zero.
+// Decryption reads the work factor from the encrypted data.
+//
+//nolint:gochecknoglobals // set by the tests of the packages that use this one
+var ScryptWorkFactor int
+
 // EncryptToRecipient encrypts data to a recipient using age
 // The data parameter should be a LockedBuffer for secure memory handling
 func EncryptToRecipient(
@@ -142,6 +152,10 @@ func EncryptWithPassphrase(
 		return nil, fmt.Errorf("failed to create scrypt recipient: %w", err)
 	}
 
+	if ScryptWorkFactor != 0 {
+		recipient.SetWorkFactor(ScryptWorkFactor)
+	}
+
 	return EncryptToRecipient(data, recipient)
 }
 

internal/secret/secret_test.go

@@ -25,6 +25,14 @@ var (
 	errNotImplementedInMock = errors.New("not implemented in mock")
 )
 
+// TestMain makes passphrase encryption in the tests cheap; see
+// ScryptWorkFactor.
+func TestMain(m *testing.M) {
+	ScryptWorkFactor = 1
+
+	os.Exit(m.Run())
+}
+
 // MockVault is a test implementation of the VaultInterface
 type MockVault struct {
 	name            string