Add support for --version flag

cmd/root.go

@@ -48,8 +48,12 @@ func newRootCommand(gs *state.GlobalState) *rootCommand {
 		SilenceUsage:      true,
 		SilenceErrors:     true,
 		PersistentPreRunE: c.persistentPreRunE,
+		Version:           versionString(),
 	}
 
+	rootCmd.SetVersionTemplate(
+		`{{with .Name}}{{printf "%s " .}}{{end}}{{printf "v%s\n" .Version}}`,
+	)
 	rootCmd.PersistentFlags().AddFlagSet(rootCmdPersistentFlagSet(gs))
 	rootCmd.SetArgs(gs.CmdArgs[1:])
 	rootCmd.SetOut(gs.Stdout)

cmd/tests/cmd_run_test.go

@@ -37,15 +37,25 @@ import (
 func TestVersion(t *testing.T) {
 	t.Parallel()
 
+	tests := map[string]struct {
+		args string
+	}{
+		"flag":       {"--version"},
+		"subcommand": {"version"},
+	}
+
 	ts := NewGlobalTestState(t)
-	ts.CmdArgs = []string{"k6", "version"}
-	cmd.ExecuteWithGlobalState(ts.GlobalState)
 
-	stdout := ts.Stdout.String()
-	assert.Contains(t, stdout, "k6 v"+consts.Version)
-	assert.Contains(t, stdout, runtime.Version())
-	assert.Contains(t, stdout, runtime.GOOS)
-	assert.Contains(t, stdout, runtime.GOARCH)
+	for _, tc := range tests {
+		ts.CmdArgs = []string{"k6", tc.args}
+		cmd.ExecuteWithGlobalState(ts.GlobalState)
+
+		stdout := ts.Stdout.String()
+		assert.Contains(t, stdout, "k6 v"+consts.Version)
+		assert.Contains(t, stdout, runtime.Version())
+		assert.Contains(t, stdout, runtime.GOOS)
+		assert.Contains(t, stdout, runtime.GOARCH)
+	}
 
 	assert.Empty(t, ts.Stderr.Bytes())
 	assert.Empty(t, ts.LoggerHook.Drain())

cmd/version.go

@@ -10,23 +10,30 @@ import (
 	"go.k6.io/k6/lib/consts"
 )
 
+func versionString() string {
+	v := consts.FullVersion()
+
+	if exts := ext.GetAll(); len(exts) > 0 {
+		extsDesc := make([]string, 0, len(exts))
+		for _, e := range exts {
+			extsDesc = append(extsDesc, fmt.Sprintf("  %s", e.String()))
+		}
+		v += fmt.Sprintf("\nExtensions:\n%s\n",
+			strings.Join(extsDesc, "\n"))
+	}
+	return v
+}
+
 func getCmdVersion(gs *state.GlobalState) *cobra.Command {
 	// versionCmd represents the version command.
 	return &cobra.Command{
 		Use:   "version",
 		Short: "Show application version",
 		Long:  `Show the application version and exit.`,
 		Run: func(_ *cobra.Command, _ []string) {
-			printToStdout(gs, fmt.Sprintf("k6 v%s\n", consts.FullVersion()))
-
-			if exts := ext.GetAll(); len(exts) > 0 {
-				extsDesc := make([]string, 0, len(exts))
-				for _, e := range exts {
-					extsDesc = append(extsDesc, fmt.Sprintf("  %s", e.String()))
-				}
-				printToStdout(gs, fmt.Sprintf("Extensions:\n%s\n",
-					strings.Join(extsDesc, "\n")))
-			}
+	root := cmd.Root()
+    root.SetArgs([]string{"--version"})
+	root.Execute()
 		},
 	}
 }