Add basic raw/patch unit test and call benchmark.

Author: icedream

go.mod

@@ -5,9 +5,13 @@ go 1.18
 require (
 	github.com/alecthomas/kingpin/v2 v2.4.0
 	github.com/dsnet/compress v0.0.1
+	github.com/stretchr/testify v1.8.2
 )
 
 require (
 	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/xhit/go-str2duration/v2 v2.1.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -4,6 +4,7 @@ github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 h1:s6gZFSlWYmbqAu
 github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dsnet/compress v0.0.1 h1:PlZu0n3Tuv04TzpfPbrnI0HW/YwodEXDS+oPKahKF0Q=
 github.com/dsnet/compress v0.0.1/go.mod h1:Aw8dCMJ7RioblQeTqt88akK31OvO8Dhf5JflhBbQEHo=
 github.com/dsnet/golib v0.0.0-20171103203638-1ea166775780/go.mod h1:Lj+Z9rebOhdfkVLjJ8T6VcRQv3SXugXy999NBtR9aFY=
@@ -12,11 +13,19 @@ github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgo
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/ulikunitz/xz v0.5.6/go.mod h1:2bypXElzHzzJZwzH67Y6wb67pO62Rzfn7BSiF4ABRW8=
 github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
 github.com/xhit/go-str2duration/v2 v2.1.0/go.mod h1:ohY8p+0f07DiV6Em5LKB0s2YpLtXVyJfNt1+BlmyAsU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/testing/fixtures/fixtures.go

@@ -0,0 +1,22 @@
+// Copyright (c) 2017-2025 Carl Kittelberger.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.txt file.
+
+package fixtures
+
+import _ "embed"
+
+// The updated test file.
+//
+//go:embed new.txt
+var New []byte
+
+// The original test file.
+//
+//go:embed old.txt
+var Old []byte
+
+// A fully bsdiff-formatted patch between the original and the updated test file.
+//
+//go:embed old_to_new_patch.bin
+var Patch []byte

internal/testing/fixtures/new.txt

@@ -0,0 +1,5 @@
+Lorem
+Ipsum
+Hello
+Set
+Dolem

internal/testing/fixtures/old.txt

@@ -0,0 +1,4 @@
+Lorem
+Ipsum
+Set
+Dolem

internal/testing/fixtures/old_to_new_patch.bin

@@ -0,0 +1,65 @@
+// Copyright (c) 2017-2025 Carl Kittelberger.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.txt file.
+
+package patch_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/icedream/go-bsdiff/internal/testing/fixtures"
+	"github.com/icedream/go-bsdiff/patch"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPatch(t *testing.T) {
+	t.Run("succeeds with valid patch", func(t *testing.T) {
+		oldReader := bytes.NewReader(fixtures.Old)
+		patchReader := bytes.NewReader(fixtures.Patch)
+		var buf bytes.Buffer
+
+		require.NoError(t, patch.Patch(oldReader, &buf, patchReader))
+		require.Equal(t, fixtures.New, buf.Bytes())
+	})
+
+	t.Run("fails with invalid patch", func(t *testing.T) {
+		oldReader := bytes.NewReader(fixtures.Old)
+		patchReader := bytes.NewReader([]byte("invalid patch"))
+		var buf bytes.Buffer
+
+		require.Error(t, patch.Patch(oldReader, &buf, patchReader))
+		require.Empty(t, buf.Bytes())
+	})
+
+	t.Run("fails with invalid original file", func(t *testing.T) {
+		// TODO - bsdiff currently seems to return 0 code...?
+		t.Skip()
+
+		oldReader := bytes.NewReader([]byte("bad file"))
+		patchReader := bytes.NewReader(fixtures.Patch)
+		var buf bytes.Buffer
+
+		require.Error(t, patch.Patch(oldReader, &buf, patchReader))
+		require.Empty(t, buf.Bytes())
+	})
+}
+
+func BenchmarkPatch(b *testing.B) {
+	// make sure we start in the middle of the loop from exactly 0 time passed
+	b.StopTimer()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		oldReader := bytes.NewReader(fixtures.Old)
+		patchReader := bytes.NewReader(fixtures.Patch)
+		var buf bytes.Buffer
+
+		// measure actual patch
+		b.StartTimer()
+		err := patch.Patch(oldReader, &buf, patchReader)
+		b.StopTimer()
+
+		require.NoError(b, err)
+	}
+}