Adding cmd/version_test.go file, handles when we can and can\'t get the version

Author: deckarep

cmd/version.go

@@ -27,11 +27,14 @@ package cmd
 
 import (
 	"fmt"
+	"io"
+	"os"
 	"strings"
 
-	"github.com/deckarep/tips/pkg"
 	"github.com/deckarep/tips/pkg/tailscale_cli"
 
+	"github.com/deckarep/tips/pkg"
+
 	"github.com/spf13/cobra"
 )
 
@@ -44,14 +47,20 @@ var versionCmd = &cobra.Command{
 	Short: pkg.AppShortName + " empowers you to wrangle your Tailnet",
 	Long:  pkg.AppLongName + " empowers you to manage your Tailscale cluster like a pro",
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Printf("%s (%s) %s\n", pkg.AppLongName, pkg.AppShortName, pkg.AppVersion)
-		fmt.Println()
-
-		cliVersion, err := tailscale_cli.GetVersion()
-		if err == nil {
-			fmt.Println("Tailscale CLI")
-			fmt.Println(strings.Repeat("*", 32))
-			fmt.Println(cliVersion)
-		}
+		printVersion(os.Stdout, tailscale_cli.GetVersion)
 	},
 }
+
+type versionGetter func() (string, error)
+
+func printVersion(w io.Writer, getVersion versionGetter) {
+	fmt.Fprintf(w, "%s (%s) %s\n", pkg.AppLongName, pkg.AppShortName, pkg.AppVersion)
+	fmt.Fprintln(w)
+
+	cliVersion, err := getVersion()
+	if err == nil {
+		fmt.Fprintln(w, "Tailscale CLI")
+		fmt.Fprintln(w, strings.Repeat("*", 32))
+		fmt.Fprintln(w, cliVersion)
+	}
+}

cmd/version_test.go

@@ -0,0 +1,35 @@
+package cmd
+
+import (
+	"bytes"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPrintVersion(t *testing.T) {
+	var b bytes.Buffer
+
+	// When we can get the version.
+	var getVersion = func() (string, error) {
+		return "whatever 2.0.1", nil
+	}
+
+	printVersion(&b, getVersion)
+
+	assert.Equal(t, b.String(),
+		"Tailscale IPs (tips) 0.0.1\n\nTailscale CLI\n********************************\nwhatever 2.0.1\n")
+
+	b.Reset()
+
+	// When we can't get the version.
+	getVersion = func() (string, error) {
+		return "", errors.New("couldn't get version cause some crazy reason!")
+	}
+
+	printVersion(&b, getVersion)
+
+	assert.Equal(t, b.String(),
+		"Tailscale IPs (tips) 0.0.1\n\n")
+}