Ensure that the upgraded version is really greater

go.mod

@@ -5,5 +5,6 @@ go 1.16
 require (
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/spf13/cobra v1.3.0
+	golang.org/x/mod v0.5.1
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )

go.sum

@@ -387,6 +387,8 @@ golang.org/x/mod v0.4.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.4.1/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.5.0/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
+golang.org/x/mod v0.5.1 h1:OJxoQ/rynoF0dcCdI7cLPktw/hR2cueqYfjm43oqK38=
+golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181023162649-9b4f9f5ad519/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=

update/main.go

@@ -9,6 +9,8 @@ import (
 	"os"
 	"runtime"
 	"time"
+
+	"golang.org/x/mod/semver"
 )
 
 var exe, _ = os.Executable()
@@ -62,15 +64,17 @@ func CheckLatestVersion() (string, []Asset, error) {
 		return "", nil, errors.New("No release found")
 	}
 
-	// if the current version is the same as the latest version, don't update
+	// compare the current version, if the current version is the same or lower than the latest version, don't update
-	if Version == release.TagName {
+	versions := []string{Version, release.TagName}
-		fmt.Println("You are using the latest version")
+	semver.Sort(versions)
-		return "", nil, errors.New("You are using the latest version")
+	if versions[1] == Version {
+		return "", nil, errors.New("Current version is the latest version")
 	}
 
 	return release.TagName, release.Assets, nil
 }
 
+// DownloadLatestVersion will download the latest version of katenary.
 func DownloadLatestVersion(assets []Asset) error {
 	// Download the latest version
 	fmt.Println("Downloading the latest version...")
@@ -118,6 +122,7 @@ func DownloadLatestVersion(assets []Asset) error {
 	return err
 }
 
+// DownloadFile will download a url to a local file. It also ensure that the file is executable.
 func DownloadFile(url, exe string) error {
 	// Download the url binary to exe path
 	resp, err := http.Get(url)

update/update_test.go

@@ -34,3 +34,19 @@ func TestDownloadLatestRelease(t *testing.T) {
 		t.Errorf("Error: %s", err)
 	}
 }
+
+func TestAlreadyUpToDate(t *testing.T) {
+	Version = "99999.999.99"
+	exe = "/tmp/test-katenary"
+	defer os.Remove(exe)
+
+	// Call the version check
+	version, _, err := CheckLatestVersion()
+
+	if err == nil {
+		t.Errorf("Error: %s", err)
+	}
+
+	t.Log("Version is already the most recent", version)
+
+}