Add FileSizeInBytes to FileManager

fileutil/fileutil.go

@@ -17,6 +17,7 @@ type FileManager interface {
 	RemoveAll(path string) error
 	Write(path string, value string, perm os.FileMode) error
 	WriteBytes(path string, value []byte) error
+	FileSizeInBytes(pth string) (float64, error)
 }
 
 type fileManager struct {
@@ -89,3 +90,15 @@ func (fileManager) ensureSavePath(savePath string) error {
 func (f fileManager) WriteBytes(path string, value []byte) error {
 	return os.WriteFile(path, value, 0600)
 }
+
+func (fileManager) FileSizeInBytes(pth string) (float64, error) {
+	if pth == "" {
+		return 0, errors.New("No path provided")
+	}
+	fileInf, err := os.Lstat(pth)
+	if err != nil {
+		return 0, err
+	}
+
+	return float64(fileInf.Size()), nil
+}

fileutil/fileutil_test.go

@@ -5,8 +5,9 @@ import (
 	"path/filepath"
 	"testing"
 
-	"github.com/bitrise-io/go-utils/v2/pathutil"
 	"github.com/stretchr/testify/require"
+
+	"github.com/bitrise-io/go-utils/v2/pathutil"
 )
 
 func TestWrite(t *testing.T) {
@@ -52,3 +53,32 @@ func TestWrite(t *testing.T) {
 		require.Error(t, manager.WriteBytes(tmpFilePath, []byte("test string")), "open "+tmpFilePath+": no such file or directory")
 	}
 }
+
+func TestFileSizeInBytes(t *testing.T) {
+	provider := pathutil.NewPathProvider()
+	tmpDirPath, err := provider.CreateTempDir("go-utils-test-")
+	require.NoError(t, err)
+	manager := NewFileManager()
+	t.Run("Success when existing file provided", func(t *testing.T) {
+		const content = "test string"
+		{
+			tmpFilePath := filepath.Join(tmpDirPath, "FileSizeInBytes-success.txt")
+			require.NoError(t, manager.Write(tmpFilePath, content, 0600))
+
+			fileSize, err := manager.FileSizeInBytes(tmpFilePath)
+			require.NoError(t, err)
+			require.Equal(t, float64(len([]byte(content))), fileSize)
+		}
+	})
+
+	t.Run("Failure when non-existing path", func(t *testing.T) {
+		tmpFilePath := filepath.Join(tmpDirPath, "dir-does-not-exist-2", "FileSizeInBytes-error.txt")
+		_, err := manager.FileSizeInBytes(tmpFilePath)
+		require.EqualError(t, err, "lstat "+tmpFilePath+": no such file or directory")
+	})
+
+	t.Run("Failure when path is empty string", func(t *testing.T) {
+		_, err := manager.FileSizeInBytes("")
+		require.EqualError(t, err, "No path provided")
+	})
+}