test(version): add a test function to test the result of the version …

…command

cmd/version.go

@@ -1,3 +1,5 @@
+package cmd
+
 /*
 Copyright © 2021 NAME HERE <EMAIL ADDRESS>
 
@@ -13,28 +15,33 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-package cmd
 
 import (
 	"fmt"
 
 	"github.com/spf13/cobra"
 )
 
-// versionCmd represents the version command
-var versionCmd = &cobra.Command{
-	Use:   "version",
-	Short: "The version of the project",
-	Long: `The current version of the project.
-
-	This projects follows the semantic versioning standard.`,
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("v0.1.0")
-	},
+// NewVersionCmd return a versionCmd instance
+func NewVersionCmd() *cobra.Command {
+
+	// versionCmd represents the version command
+	versionCmd := &cobra.Command{
+		Use:   "version",
+		Short: "The version of the project",
+		Long: `The current version of the project.
+		This projects follows the semantic versioning standard.`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			fmt.Fprintln(cmd.OutOrStdout(), "v0.1.0")
+			return nil
+		},
+	}
+
+	return versionCmd
 }
 
 func init() {
-	rootCmd.AddCommand(versionCmd)
+	rootCmd.AddCommand(NewVersionCmd())
 
 	// Here you will define your flags and configuration settings.
 

cmd/version_test.go

@@ -0,0 +1,23 @@
+package cmd
+
+import (
+	"bytes"
+	"io/ioutil"
+	"strings"
+	"testing"
+)
+
+func TestVersionCmd(t *testing.T) {
+	cmd := NewVersionCmd()
+	b := bytes.NewBufferString("")
+	cmd.SetOut(b)
+	cmd.Execute()
+	out, err := ioutil.ReadAll(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !strings.Contains(string(out), "v0.1.0") {
+		t.Fatalf("expected \"%s\" got \"%s\"", "v0.1.0", string(out))
+	}
+}