From bcab5486171e0dd09f8fc4dcf87b58031fc8f13a Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Fri, 29 Apr 2022 23:41:03 +0200
Subject: [PATCH] pack: slightly expand testing of compressed blobs

---
 internal/pack/pack.go               | 16 ++++++++---
 internal/pack/pack_internal_test.go | 42 +++++++++++++++++++++++++----
 2 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/internal/pack/pack.go b/internal/pack/pack.go
index 697a14a5d..2d7a5c3fb 100644
--- a/internal/pack/pack.go
+++ b/internal/pack/pack.go
@@ -54,10 +54,18 @@ var plainEntrySize = uint(binary.Size(restic.BlobType(0)) + headerLengthSize + l
 // headerEntry describes the format of header entries. It serves only as
 // documentation.
 type headerEntry struct {
-	Type             uint8
-	Length           uint32
-	ID               restic.ID
-	CompressedLength uint32
+	Type   uint8
+	Length uint32
+	ID     restic.ID
+}
+
+// compressedHeaderEntry describes the format of header entries for compressed blobs.
+// It serves only as documentation.
+type compressedHeaderEntry struct {
+	Type               uint8
+	Length             uint32
+	UncompressedLength uint32
+	ID                 restic.ID
 }
 
 // Finalize writes the header for all added blobs and finalizes the pack.
diff --git a/internal/pack/pack_internal_test.go b/internal/pack/pack_internal_test.go
index 93d04f18e..c1a4867ea 100644
--- a/internal/pack/pack_internal_test.go
+++ b/internal/pack/pack_internal_test.go
@@ -13,7 +13,7 @@ import (
 
 func TestParseHeaderEntry(t *testing.T) {
 	h := headerEntry{
-		Type:   0, // Blob.
+		Type:   0, // Blob
 		Length: 100,
 	}
 	for i := range h.ID {
@@ -28,21 +28,53 @@ func TestParseHeaderEntry(t *testing.T) {
 	rtest.Equals(t, restic.DataBlob, b.Type)
 	rtest.Equals(t, plainEntrySize, size)
 	t.Logf("%v %v", h.ID, b.ID)
-	rtest.Assert(t, bytes.Equal(h.ID[:], b.ID[:]), "id mismatch")
+	rtest.Equals(t, h.ID[:], b.ID[:])
 	rtest.Equals(t, uint(h.Length), b.Length)
+	rtest.Equals(t, uint(0), b.UncompressedLength)
+
+	c := compressedHeaderEntry{
+		Type:               2, // compressed Blob
+		Length:             100,
+		UncompressedLength: 200,
+	}
+	for i := range c.ID {
+		c.ID[i] = byte(i)
+	}
+
+	buf = new(bytes.Buffer)
+	_ = binary.Write(buf, binary.LittleEndian, &c)
+
+	b, size, err = parseHeaderEntry(buf.Bytes())
+	rtest.OK(t, err)
+	rtest.Equals(t, restic.DataBlob, b.Type)
+	rtest.Equals(t, entrySize, size)
+	t.Logf("%v %v", c.ID, b.ID)
+	rtest.Equals(t, c.ID[:], b.ID[:])
+	rtest.Equals(t, uint(c.Length), b.Length)
+	rtest.Equals(t, uint(c.UncompressedLength), b.UncompressedLength)
+}
+
+func TestParseHeaderEntryErrors(t *testing.T) {
+	h := headerEntry{
+		Type:   0, // Blob
+		Length: 100,
+	}
+	for i := range h.ID {
+		h.ID[i] = byte(i)
+	}
 
 	h.Type = 0xae
-	buf.Reset()
+	buf := new(bytes.Buffer)
 	_ = binary.Write(buf, binary.LittleEndian, &h)
 
-	b, _, err = parseHeaderEntry(buf.Bytes())
+	_, _, err := parseHeaderEntry(buf.Bytes())
 	rtest.Assert(t, err != nil, "no error for invalid type")
 
 	h.Type = 0
 	buf.Reset()
 	_ = binary.Write(buf, binary.LittleEndian, &h)
 
-	b, _, err = parseHeaderEntry(buf.Bytes()[:plainEntrySize-1])
+	_, _, err = parseHeaderEntry(buf.Bytes()[:plainEntrySize-1])
 	rtest.Assert(t, err != nil, "no error for short input")
 }