Add previously-untracked snapshot removal and verify tests

These test files existed locally and ran in the suite but were never
committed due to the old .gitignore 'vaultik' pattern matching the
internal/vaultik/ directory.

internal/vaultik/verify_test.go

@@ -0,0 +1,92 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"io"
+	"testing"
+
+	"git.eeqj.de/sneak/vaultik/internal/crypto"
+	"github.com/klauspost/compress/zstd"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestTeeReaderWithDecryption tests that TeeReader correctly hashes all encrypted
+// bytes when streaming through age decryption and zstd decompression.
+// This validates the verification path: hash encrypted blob -> decrypt -> decompress.
+func TestTeeReaderWithDecryption(t *testing.T) {
+	// Test data - use random data that doesn't compress well (5MB)
+	testData := make([]byte, 5*1024*1024)
+	_, err := rand.Read(testData)
+	require.NoError(t, err)
+
+	// Compress the data
+	var compressedBuf bytes.Buffer
+	compressor, err := zstd.NewWriter(&compressedBuf, zstd.WithEncoderLevel(zstd.SpeedDefault))
+	require.NoError(t, err)
+	_, err = compressor.Write(testData)
+	require.NoError(t, err)
+	err = compressor.Close()
+	require.NoError(t, err)
+
+	// Encrypt the compressed data
+	testRecipient := "age1cplgrwj77ta54dnmydvvmzn64ltk83ankxl5sww04mrtmu62kv3s89gmvv"
+	testSecretKey := "AGE-SECRET-KEY-1C77PYNTHXSHNNC6EYR2W52UWYXACXA5JT00J9CCW9986M3XY87PSGP89AQ"
+
+	encryptor, err := crypto.NewEncryptor([]string{testRecipient})
+	require.NoError(t, err)
+
+	var encryptedBuf bytes.Buffer
+	err = encryptor.EncryptStream(&encryptedBuf, bytes.NewReader(compressedBuf.Bytes()))
+	require.NoError(t, err)
+
+	encryptedData := encryptedBuf.Bytes()
+
+	// Calculate the expected hash of the encrypted data directly
+	expectedHash := sha256.Sum256(encryptedData)
+	expectedHashStr := hex.EncodeToString(expectedHash[:])
+
+	t.Logf("Encrypted data size: %d bytes", len(encryptedData))
+	t.Logf("Expected hash: %s", expectedHashStr)
+
+	// Now simulate what verifyBlob does: use TeeReader to hash while decrypting
+	decryptor, err := crypto.NewDecryptor(testSecretKey)
+	require.NoError(t, err)
+
+	// Create hasher and tee reader
+	hasher := sha256.New()
+	reader := bytes.NewReader(encryptedData)
+	teeReader := io.TeeReader(reader, hasher)
+
+	// Decrypt through the tee reader
+	decryptedReader, err := decryptor.DecryptStream(teeReader)
+	require.NoError(t, err)
+
+	// Decompress
+	decompressor, err := zstd.NewReader(decryptedReader)
+	require.NoError(t, err)
+	defer decompressor.Close()
+
+	// Read all decompressed data (simulating chunk verification)
+	decompressedData, err := io.ReadAll(decompressor)
+	require.NoError(t, err)
+
+	// Verify we got the original data back
+	assert.Equal(t, testData, decompressedData, "Decompressed data should match original")
+
+	// Drain remaining decompressed data (should be 0)
+	remaining, err := io.Copy(io.Discard, decompressor)
+	require.NoError(t, err)
+	assert.Equal(t, int64(0), remaining, "No remaining decompressed data")
+
+	// Calculate hash from tee reader
+	calculatedHashStr := hex.EncodeToString(hasher.Sum(nil))
+	t.Logf("Calculated hash (before drain): %s", calculatedHashStr)
+
+	// Verify the hash matches the direct hash of encrypted data
+	assert.Equal(t, expectedHashStr, calculatedHashStr,
+		"Hash calculated via TeeReader should match direct hash of encrypted data")
+}