Rename HashReader -> HashAppendReader, add HashingReader

backend/reader_test.go

@@ -0,0 +1,80 @@
+package backend_test
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/sha256"
+	"io"
+	"io/ioutil"
+	"testing"
+
+	"github.com/restic/restic/backend"
+)
+
+func TestHashAppendReader(t *testing.T) {
+	tests := []int{5, 23, 2<<18 + 23, 1 << 20}
+
+	for _, size := range tests {
+		data := make([]byte, size)
+		_, err := io.ReadFull(rand.Reader, data)
+		if err != nil {
+			t.Fatalf("ReadFull: %v", err)
+		}
+
+		expectedHash := sha256.Sum256(data)
+
+		rd := backend.NewHashAppendReader(bytes.NewReader(data), sha256.New())
+
+		target := bytes.NewBuffer(nil)
+		n, err := io.Copy(target, rd)
+		ok(t, err)
+
+		assert(t, n == int64(size)+int64(len(expectedHash)),
+			"HashAppendReader: invalid number of bytes read: got %d, expected %d",
+			n, size+len(expectedHash))
+
+		r := target.Bytes()
+		resultingHash := r[len(r)-len(expectedHash):]
+		assert(t, bytes.Equal(expectedHash[:], resultingHash),
+			"HashAppendReader: hashes do not match: expected %02x, got %02x",
+			expectedHash, resultingHash)
+
+		// try to read again, must return io.EOF
+		n2, err := rd.Read(make([]byte, 100))
+		assert(t, n2 == 0, "HashAppendReader returned %d additional bytes", n)
+		assert(t, err == io.EOF, "HashAppendReader returned %v instead of EOF", err)
+	}
+}
+
+func TestHashingReader(t *testing.T) {
+	tests := []int{5, 23, 2<<18 + 23, 1 << 20}
+
+	for _, size := range tests {
+		data := make([]byte, size)
+		_, err := io.ReadFull(rand.Reader, data)
+		if err != nil {
+			t.Fatalf("ReadFull: %v", err)
+		}
+
+		expectedHash := sha256.Sum256(data)
+
+		rd := backend.NewHashingReader(bytes.NewReader(data), sha256.New())
+
+		n, err := io.Copy(ioutil.Discard, rd)
+		ok(t, err)
+
+		assert(t, n == int64(size),
+			"HashAppendReader: invalid number of bytes read: got %d, expected %d",
+			n, size+len(expectedHash))
+
+		resultingHash := rd.Sum(nil)
+		assert(t, bytes.Equal(expectedHash[:], resultingHash),
+			"HashAppendReader: hashes do not match: expected %02x, got %02x",
+			expectedHash, resultingHash)
+
+		// try to read again, must return io.EOF
+		n2, err := rd.Read(make([]byte, 100))
+		assert(t, n2 == 0, "HashAppendReader returned %d additional bytes", n)
+		assert(t, err == io.EOF, "HashAppendReader returned %v instead of EOF", err)
+	}
+}