refactor(internal/sample): export LibrarianVersion constant (#3812)

Move the constant testLibrarianVersion to internal/sample, and use
sample.LibrarianVersion throughout tests.

Fixes #3793

Author: julieqiu

internal/librarian/tidy_test.go

@@ -23,11 +23,10 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/googleapis/librarian/internal/config"
+	"github.com/googleapis/librarian/internal/sample"
 	"github.com/googleapis/librarian/internal/yaml"
 )
 
-const testLibrarianVersion = "v0.1.0"
-
 func TestValidateLibraries(t *testing.T) {
 	for _, test := range []struct {
 		name      string
@@ -175,7 +174,7 @@ libraries:
     version: "1.0.0"
   - name: google-cloud-bigquery-v1
     version: "2.0.0"
-`, testLibrarianVersion)
+`, sample.LibrarianVersion)
 	if err := os.WriteFile(configPath, []byte(configContent), 0644); err != nil {
 		t.Fatal(err)
 	}
@@ -187,8 +186,8 @@ libraries:
 	if err != nil {
 		t.Fatal(err)
 	}
-	if cfg.Version != testLibrarianVersion {
-		t.Errorf("version = %q, want %q", cfg.Version, testLibrarianVersion)
+	if cfg.Version != sample.LibrarianVersion {
+		t.Errorf("version = %q, want %q", cfg.Version, sample.LibrarianVersion)
 	}
 
 	var got []string

internal/librarianops/librarianops_test.go

@@ -29,8 +29,6 @@ import (
 	"github.com/googleapis/librarian/internal/yaml"
 )
 
-const testLibrarianVersion = "v0.1.0"
-
 func TestGenerateCommand(t *testing.T) {
 	for _, test := range []struct {
 		name    string
@@ -158,13 +156,13 @@ func TestUpdateLibrarianVersion(t *testing.T) {
 	configPath := filepath.Join(repoDir, "librarian.yaml")
 	initialConfig := &config.Config{
 		Language: "rust",
-		Version:  "v0.1.0",
+		Version:  sample.LibrarianVersion,
 	}
 	if err := yaml.Write(configPath, initialConfig); err != nil {
 		t.Fatal(err)
 	}
 
-	newVersion := testLibrarianVersion
+	newVersion := "v0.2.0"
 	if err := updateLibrarianVersion(newVersion, repoDir); err != nil {
 		t.Fatal(err)
 	}

internal/sample/sample.go

@@ -23,6 +23,8 @@ import (
 )
 
 const (
+	// LibrarianVersion is the librarian version used in [Config].
+	LibrarianVersion = "v0.1.0"
 	// Lib1Name is the name of the first library added to the [Config].
 	Lib1Name = "google-cloud-storage"
 	// Lib2Name is the name of the second library added to the [Config].
@@ -71,7 +73,7 @@ var (
 func Config() *config.Config {
 	return &config.Config{
 		Language: "fake",
-		Version:  "v0.1.0",
+		Version:  LibrarianVersion,
 		Default:  &config.Default{},
 		Release: &config.Release{
 			Remote: "origin",