fix: Enable to display current command's version (#20)

.goreleaser.yml

@@ -7,6 +7,8 @@ builds:
       - amd64
     env:
       - CGO_ENABLED=0
+    ldflags:
+      - "-X github.com/screwdriver-cd/sd-local/cmd.version={{ .Version }}"
 
 archives:
   - format: binary

cmd/root.go

@@ -21,6 +21,7 @@ func Execute() error {
 	rootCmd.AddCommand(
 		newBuildCmd(),
 		config.NewConfigCmd(),
+		newVersionCmd(),
 	)
 	return rootCmd.Execute()
 }

cmd/version.go

@@ -0,0 +1,23 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	// version is embedded when building this command using ldflags.
+	// if nothing is embedded, version is "dev"
+	version = "dev"
+)
+
+func newVersionCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:   "version",
+		Short: "Display command's version.",
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Fprintln(cmd.OutOrStdout(), version)
+		},
+	}
+}

cmd/version_test.go

@@ -0,0 +1,46 @@
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVersionCmd(t *testing.T) {
+	cases := []struct {
+		name    string
+		version string
+		expect  string
+	}{
+		{
+			name:    "0.0.1 is embedded as version",
+			version: "0.0.1",
+			expect:  "0.0.1",
+		},
+		{
+			name:    "0.1.0 is embedded as version",
+			version: "0.1.0",
+			expect:  "0.1.0",
+		},
+		{
+			name:   "version is not embedded",
+			expect: "dev",
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			tv := version
+			if c.version != "" {
+				version = c.version
+			}
+			defer func() { version = tv }()
+			cmd := newVersionCmd()
+			buf := bytes.NewBuffer(nil)
+			cmd.SetOut(buf)
+			cmd.Execute()
+			assert.Equal(t, fmt.Sprintf("%s\n", c.expect), buf.String())
+		})
+	}
+}