fix: Improve kpt version command output and add comprehensive tests

run/run.go

@@ -153,13 +153,23 @@ func newHelp(e []string, c *cobra.Command) func(command *cobra.Command, strings
 	}
 }
 
+// version is set at build time via ldflags
 var version = "unknown"
 
 var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Print the version number of kpt",
+	Long: `Print the semantic version number of kpt.
+
+The version follows semantic versioning (semver) format: vMAJOR.MINOR.PATCH
+For more information, see https://semver.org`,
 	Run: func(_ *cobra.Command, _ []string) {
-		fmt.Printf("%s\n", version)
+		// Display version in a clear format
+		if version == "unknown" {
+			fmt.Println("kpt version: unknown (development build)")
+		} else {
+			fmt.Printf("kpt version: %s\n", version)
+		}
 	},
 }
 

run/run_test.go

@@ -0,0 +1,132 @@
+// Copyright 2026 The kpt Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// 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 run
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestVersionCommand(t *testing.T) {
+	tests := []struct {
+		name            string
+		version         string
+		expectedContain string
+	}{
+		{
+			name:            "semantic version",
+			version:         "v1.0.0",
+			expectedContain: "kpt version: v1.0.0",
+		},
+		{
+			name:            "development version",
+			version:         "v1.0.0-dev",
+			expectedContain: "kpt version: v1.0.0-dev",
+		},
+		{
+			name:            "unknown version",
+			version:         "unknown",
+			expectedContain: "kpt version: unknown (development build)",
+		},
+		{
+			name:            "version with build metadata",
+			version:         "v1.0.0+abc123",
+			expectedContain: "kpt version: v1.0.0+abc123",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original version
+			originalVersion := version
+			defer func() { version = originalVersion }()
+
+			// Set test version
+			version = tt.version
+
+			// Capture output
+			var buf bytes.Buffer
+			versionCmd.SetOut(&buf)
+			versionCmd.SetErr(&buf)
+
+			// Run command
+			err := versionCmd.RunE(versionCmd, []string{})
+			if err != nil {
+				t.Fatalf("version command failed: %v", err)
+			}
+
+			// Check output
+			output := buf.String()
+			if !strings.Contains(output, tt.expectedContain) {
+				t.Errorf("expected output to contain %q, got %q", tt.expectedContain, output)
+			}
+		})
+	}
+}
+
+func TestVersionCommandFormat(t *testing.T) {
+	// Save original version
+	originalVersion := version
+	defer func() { version = originalVersion }()
+
+	// Test semantic version format
+	version = "v1.0.0"
+
+	var buf bytes.Buffer
+	versionCmd.SetOut(&buf)
+	versionCmd.SetErr(&buf)
+
+	err := versionCmd.RunE(versionCmd, []string{})
+	if err != nil {
+		t.Fatalf("version command failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Verify format: "kpt version: vX.Y.Z\n"
+	if !strings.HasPrefix(output, "kpt version: v") {
+		t.Errorf("expected output to start with 'kpt version: v', got %q", output)
+	}
+
+	if !strings.HasSuffix(output, "\n") {
+		t.Errorf("expected output to end with newline, got %q", output)
+	}
+}
+
+func TestVersionCommandUnknown(t *testing.T) {
+	// Save original version
+	originalVersion := version
+	defer func() { version = originalVersion }()
+
+	// Test unknown version
+	version = "unknown"
+
+	var buf bytes.Buffer
+	versionCmd.SetOut(&buf)
+	versionCmd.SetErr(&buf)
+
+	err := versionCmd.RunE(versionCmd, []string{})
+	if err != nil {
+		t.Fatalf("version command failed: %v", err)
+	}
+
+	output := buf.String()
+
+	// Verify it shows development build message
+	if !strings.Contains(output, "development build") {
+		t.Errorf("expected output to contain 'development build' for unknown version, got %q", output)
+	}
+}