add a simple test

Author: tgvashworth

cli-files/go-ls/cmd/root.go

@@ -7,32 +7,36 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var rootCmd = &cobra.Command{
-	Use:   "go-ls",
-	Short: "go-ls is a re-implementation of the ls command",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		// By default, ls the current directory
-		dir := "."
-		// If an argument was passed, use the first as our directory
-		if len(args) > 0 {
-			dir = args[0]
-		}
+func NewRoodCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:   "go-ls",
+		Short: "go-ls is a re-implementation of the ls command",
+		Args:  cobra.ArbitraryArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			// By default, ls the current directory
+			dir := "."
+			// If an argument was passed, use the first as our directory
+			if len(args) > 0 {
+				dir = args[0]
+			}
 
-		// Read this directory to get a list of files
-		// https://pkg.go.dev/os#ReadDir
-		files, err := os.ReadDir(dir)
-		if err != nil {
-			return err
-		}
-		// Iterate through each file in the directory, printing the file name
-		for _, file := range files {
-			fmt.Println(file.Name())
-		}
-		return nil
-	},
+			// Read this directory to get a list of files
+			// https://pkg.go.dev/os#ReadDir
+			files, err := os.ReadDir(dir)
+			if err != nil {
+				return err
+			}
+			// Iterate through each file in the directory, printing the file name
+			for _, file := range files {
+				fmt.Fprintln(cmd.OutOrStdout(), file.Name())
+			}
+			return nil
+		},
+	}
 }
 
 func Execute() {
+	rootCmd := NewRoodCmd()
 	if err := rootCmd.Execute(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)

cli-files/go-ls/cmd/root_test.go

@@ -0,0 +1,25 @@
+package cmd
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+)
+
+func TestRootCmd(t *testing.T) {
+	cmd := NewRoodCmd()
+	b := bytes.NewBufferString("")
+	cmd.SetOut(b)
+	cmd.SetArgs([]string{})
+	cmd.Execute()
+	out, err := ioutil.ReadAll(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := `root.go
+root_test.go
+`
+	if string(out) != expected {
+		t.Fatalf("expected \"%s\" got \"%s\"", expected, string(out))
+	}
+}