Extract qemuimg package in a test module

The module includes the qemuimg package, providing now only
qemuimg.Convert(). I plan to add qemuimg.Create(), qemuimg.Info(),
qemuimg.Map(), and qemuimg.Compare().

This makes the code nicer to work with, but adds a test only dependency.
The qcow2reader tests use now qemu2reader_test package, so the
dependency should be built only for tests.

The qemuimg test package will also be useful for other project using
this library, since testing code using the library typically requires
creating, converting and comparing qcow2 images.

Signed-off-by: Nir Soffer <[email protected]>

Author: nirs

go.mod

@@ -1,3 +1,8 @@
 module github.com/lima-vm/go-qcow2reader
 
 go 1.20
+
+// Testing requirements
+require github.com/lima-vm/go-qcow2reader/test v0.4.0
+
+replace github.com/lima-vm/go-qcow2reader/test v0.4.0 => ./test

qcow2reader_test.go

@@ -1,26 +1,21 @@
-package qcow2reader
+package qcow2reader_test
 
 import (
-	"bytes"
-	"errors"
 	"fmt"
 	"io"
 	"math/rand"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"testing"
 
+	"github.com/lima-vm/go-qcow2reader"
 	"github.com/lima-vm/go-qcow2reader/convert"
-	"github.com/lima-vm/go-qcow2reader/image"
-	"github.com/lima-vm/go-qcow2reader/image/qcow2"
+	"github.com/lima-vm/go-qcow2reader/test/qemuimg"
 )
 
 const (
 	MiB = int64(1) << 20
 	GiB = int64(1) << 30
-
-	CompressionTypeNone = qcow2.CompressionType(255)
 )
 
 // Benchmark completely empty sparse image (0% utilization).  This is the best
@@ -33,7 +28,7 @@ func Benchmark0p(b *testing.B) {
 	}
 	b.Run("qcow2", func(b *testing.B) {
 		img := base + ".qocw2"
-		if err := qemuImgConvert(base, img, qcow2.Type, CompressionTypeNone); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionNone); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -51,7 +46,7 @@ func Benchmark0p(b *testing.B) {
 	})
 	b.Run("qcow2 zlib", func(b *testing.B) {
 		img := base + ".zlib.qcow2"
-		if err := qemuImgConvert(base, img, qcow2.Type, qcow2.CompressionTypeZlib); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionZlib); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -79,7 +74,7 @@ func Benchmark50p(b *testing.B) {
 	}
 	b.Run("qcow2", func(b *testing.B) {
 		img := base + ".qocw2"
-		if err := qemuImgConvert(base, img, qcow2.Type, CompressionTypeNone); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionNone); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -97,7 +92,7 @@ func Benchmark50p(b *testing.B) {
 	})
 	b.Run("qcow2 zlib", func(b *testing.B) {
 		img := base + ".zlib.qcow2"
-		if err := qemuImgConvert(base, img, qcow2.Type, qcow2.CompressionTypeZlib); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionZlib); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -126,7 +121,7 @@ func Benchmark100p(b *testing.B) {
 	}
 	b.Run("qcow2", func(b *testing.B) {
 		img := base + ".qocw2"
-		if err := qemuImgConvert(base, img, qcow2.Type, CompressionTypeNone); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionNone); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -144,7 +139,7 @@ func Benchmark100p(b *testing.B) {
 	})
 	b.Run("qcow2 zlib", func(b *testing.B) {
 		img := base + ".zlib.qcow2"
-		if err := qemuImgConvert(base, img, qcow2.Type, qcow2.CompressionTypeZlib); err != nil {
+		if err := qemuimg.Convert(base, img, qemuimg.FormatQcow2, qemuimg.CompressionZlib); err != nil {
 			b.Fatal(err)
 		}
 		b.Run("read", func(b *testing.B) {
@@ -171,7 +166,7 @@ func benchmarkRead(b *testing.B, filename string) {
 		b.Fatal(err)
 	}
 	defer f.Close()
-	img, err := Open(f)
+	img, err := qcow2reader.Open(f)
 	if err != nil {
 		b.Fatal(err)
 	}
@@ -198,7 +193,7 @@ func benchmarkConvert(b *testing.B, filename string) {
 		b.Fatal(err)
 	}
 	defer f.Close()
-	img, err := Open(f)
+	img, err := qcow2reader.Open(f)
 	if err != nil {
 		b.Fatal(err)
 	}
@@ -289,25 +284,3 @@ func (g *Generator) Read(b []byte) (int, error) {
 	})
 	return len(b), nil
 }
-
-func qemuImgConvert(src, dst string, dstFormat image.Type, compressionType qcow2.CompressionType) error {
-	args := []string{"convert", "-O", string(dstFormat)}
-	if compressionType != CompressionTypeNone {
-		args = append(args, "-c", "-o", "compression_type="+compressionType.String())
-	}
-	args = append(args, src, dst)
-	cmd := exec.Command("qemu-img", args...)
-
-	var stderr bytes.Buffer
-	cmd.Stderr = &stderr
-
-	if err := cmd.Run(); err != nil {
-		// Return qemu-img stderr instead of the unhelpful default error (exited
-		// with status 1).
-		if _, ok := err.(*exec.ExitError); ok {
-			return errors.New(stderr.String())
-		}
-		return err
-	}
-	return nil
-}

test/go.mod

@@ -0,0 +1,3 @@
+module github.com/lima-vm/go-qcow2reader/test
+
+go 1.20

test/go.sum

@@ -0,0 +1,43 @@
+package qemuimg
+
+import (
+	"bytes"
+	"errors"
+	"os/exec"
+)
+
+type Compression string
+type Format string
+
+const (
+	// Compression types.
+	CompressionNone = Compression("")
+	CompressionZlib = Compression("zlib")
+	CompressionZstd = Compression("zstd")
+
+	// Image formats.
+	FormatQcow2 = Format("qcow2")
+	FormatRaw   = Format("raw")
+)
+
+func Convert(src, dst string, dstFormat Format, compressionType Compression) error {
+	args := []string{"convert", "-O", string(dstFormat)}
+	if compressionType != CompressionNone {
+		args = append(args, "-c", "-o", "compression_type="+string(compressionType))
+	}
+	args = append(args, src, dst)
+	cmd := exec.Command("qemu-img", args...)
+
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		// Return qemu-img stderr instead of the unhelpful default error (exited
+		// with status 1).
+		if _, ok := err.(*exec.ExitError); ok {
+			return errors.New(stderr.String())
+		}
+		return err
+	}
+	return nil
+}