smarter checking of git version

pkg/app/app.go

@@ -8,6 +8,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -138,19 +139,33 @@ func (app *App) validateGitVersion() error {
 	if err != nil {
 		return minVersionError
 	}
-	// output should be something like: 'git version 2.23.0'
-	// first number in the string should be greater than 0
-	split := strings.Split(output, " ")
-	gitVersion := split[len(split)-1]
-	majorVersion, err := strconv.Atoi(gitVersion[0:1])
-	if err != nil {
-		return minVersionError
-	}
-	if majorVersion < 2 {
-		return minVersionError
+
+	if isGitVersionValid(output) {
+		return nil
 	}
 
-	return nil
+	return minVersionError
+}
+
+func isGitVersionValid(versionStr string) bool {
+	// output should be something like: 'git version 2.23.0 (blah)'
+	re := regexp.MustCompile(`[^\d]+([\d\.]+)`)
+	matches := re.FindStringSubmatch(versionStr)
+
+	if len(matches) == 0 {
+		return false
+	}
+
+	gitVersion := matches[1]
+	majorVersion, err := strconv.Atoi(gitVersion[0:1])
+	if err != nil {
+		return false
+	}
+	if majorVersion < 2 {
+		return false
+	}
+
+	return true
 }
 
 func (app *App) setupRepo() (bool, error) {

pkg/app/app_test.go

@@ -0,0 +1,44 @@
+package app
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsGitVersionValid(t *testing.T) {
+	type scenario struct {
+		versionStr     string
+		expectedResult bool
+	}
+
+	scenarios := []scenario{
+		{
+			"",
+			false,
+		},
+		{
+			"git version 1.9.0",
+			false,
+		},
+		{
+			"git version 1.9.0 (Apple Git-128)",
+			false,
+		},
+		{
+			"git version 2.4.0",
+			true,
+		},
+		{
+			"git version 2.24.3 (Apple Git-128)",
+			true,
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.versionStr, func(t *testing.T) {
+			result := isGitVersionValid(s.versionStr)
+			assert.Equal(t, result, s.expectedResult)
+		})
+	}
+}