add unit tests for version.go

cmd/builder/internal/version.go

@@ -14,14 +14,16 @@ var (
 	version = ""
 )
 
+type debugReadBuildInfoFunc func() (info *debug.BuildInfo, ok bool)
+
 // binVersion returns the version of the binary.
 // If the version is not set, it attempts to read the build information.
 // Returns an error if the build information cannot be read.
-func binVersion() (string, error) {
+func binVersion(fn debugReadBuildInfoFunc) (string, error) {
 	if version != "" {
 		return version, nil
 	}
-	info, ok := debug.ReadBuildInfo()
+	info, ok := fn()
 	if !ok {
 		return "", fmt.Errorf("failed to read build info")
 	}
@@ -34,7 +36,7 @@ func versionCommand() *cobra.Command {
 		Short: "Version of ocb",
 		Long:  "Prints the version of the ocb binary",
 		RunE: func(cmd *cobra.Command, _ []string) error {
-			version, err := binVersion()
+			version, err := binVersion(debug.ReadBuildInfo)
 			if err != nil {
 				return err
 			}

cmd/builder/internal/version_test.go

@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package internal
+
+import (
+	"fmt"
+	"runtime/debug"
+	"testing"
+)
+
+// Mock debug.ReadBuildInfo function
+var readBuildInfo = debug.ReadBuildInfo
+
+func TestBinVersion(t *testing.T) {
+	// Test case: version is set
+	version = "v1.0.0"
+	v, err := binVersion(debug.ReadBuildInfo)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if v != "v1.0.0" {
+		t.Fatalf("expected version 'v1.0.0', got %v", v)
+	}
+
+	// // Test case: version is not set, ReadBuildInfo returns valid info
+	version = ""
+	readBuildInfo = func() (*debug.BuildInfo, bool) {
+		return &debug.BuildInfo{
+			Main: debug.Module{
+				Version: "v2.0.0",
+			},
+		}, true
+	}
+	v, err = binVersion(readBuildInfo)
+	fmt.Printf("v: %v, err: %v", v, err)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if v != "v2.0.0" {
+		t.Fatalf("expected version 'v2.0.0', got %v", v)
+	}
+
+	// Test case: version is not set, ReadBuildInfo fails
+	readBuildInfo = func() (*debug.BuildInfo, bool) {
+		return nil, false
+	}
+	v, err = binVersion(readBuildInfo)
+	if err == nil {
+		t.Fatalf("expected error, got nil")
+	}
+	if v != "" {
+		t.Fatalf("expected empty version, got %v", v)
+	}
+}