Add unit tests for parsing OpenSSH version strings

Signed-off-by: Jan Dubois <[email protected]>

Author: jandubois

go.mod

@@ -24,6 +24,7 @@ require (
 	github.com/opencontainers/go-digest v1.0.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/spf13/cobra v1.2.1
+	github.com/stretchr/testify v1.7.0
 	github.com/yalue/native_endian v1.0.1
 	golang.org/x/sys v0.0.0-20210818153620-00dd8d7831e7
 	gopkg.in/yaml.v2 v2.4.0
@@ -32,6 +33,7 @@ require (
 
 require (
 	github.com/VividCortex/ewma v1.1.1 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/digitalocean/go-libvirt v0.0.0-20201209184759-e2a69bcd5bd1 // indirect
 	github.com/fatih/color v1.10.0 // indirect
 	github.com/fsnotify/fsnotify v1.4.9 // indirect
@@ -46,6 +48,7 @@ require (
 	github.com/mgutz/ansi v0.0.0-20170206155736-9520e82c474b // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pkg/sftp v1.13.3 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5 // indirect
@@ -58,4 +61,5 @@ require (
 	google.golang.org/protobuf v1.26.0 // indirect
 	gopkg.in/djherbis/times.v1 v1.2.0 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

pkg/sshutil/sshutil.go

@@ -231,6 +231,18 @@ func SSHArgsFromOpts(opts []string) []string {
 	return args
 }
 
+func ParseOpenSSHVersion(version []byte) *semver.Version {
+	regex := regexp.MustCompile(`^OpenSSH_(\d+\.\d+)(?:p(\d+))?\b`)
+	matches := regex.FindSubmatch(version)
+	if len(matches) == 3 {
+		if len(matches[2]) == 0 {
+			matches[2] = []byte("0")
+		}
+		return semver.New(fmt.Sprintf("%s.%s", matches[1], matches[2]))
+	}
+	return &semver.Version{}
+}
+
 func detectOpenSSHVersion() semver.Version {
 	var (
 		v      semver.Version
@@ -241,15 +253,8 @@ func detectOpenSSHVersion() semver.Version {
 	if err := cmd.Run(); err != nil {
 		logrus.Warnf("failed to run %v: stderr=%q", cmd.Args, stderr.String())
 	} else {
-		regex := regexp.MustCompile(`^OpenSSH_(\d+\.\d+)(?:p(\d+))?\b`)
-		matches := regex.FindSubmatch(stderr.Bytes())
-		if len(matches) == 3 {
-			if len(matches[2]) == 0 {
-				matches[2] = []byte("0")
-			}
-			v = *semver.New(fmt.Sprintf("%s.%s", matches[1], matches[2]))
-		}
+		v = *ParseOpenSSHVersion(stderr.Bytes())
+		logrus.Debugf("OpenSSH version %s detected", v)
 	}
-	logrus.Debugf("OpenSSH version %s detected", v)
 	return v
 }

pkg/sshutil/sshutil_test.go

@@ -1,6 +1,11 @@
 package sshutil
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/coreos/go-semver/semver"
+	"github.com/stretchr/testify/assert"
+)
 
 func TestDefaultPubKeys(t *testing.T) {
 	keys, _ := DefaultPubKeys(true)
@@ -9,3 +14,12 @@ func TestDefaultPubKeys(t *testing.T) {
 		t.Logf("%s: %q", key.Filename, key.Content)
 	}
 }
+
+func TestParseOpenSSHVersion(t *testing.T) {
+	assert.True(t, ParseOpenSSHVersion([]byte("OpenSSH_8.4p1 Ubuntu")).Equal(semver.Version{8,4,1, "", ""}))
+	assert.True(t, ParseOpenSSHVersion([]byte("OpenSSH_7.6p1 Ubuntu")).LessThan(*semver.New("8.0.0")))
+	// macOS 10.15
+	assert.True(t, ParseOpenSSHVersion([]byte("OpenSSH_8.1p1, LibreSSL 2.7.3")).Equal(semver.Version{8,1,1, "", ""}))
+	// OpenBSD 5.8
+	assert.True(t, ParseOpenSSHVersion([]byte("OpenSSH_7.0, LibreSSL")).Equal(*semver.New("7.0.0")))
+}