Add comprehensive documentation to shared functions

- Add detailed docstring to setupFormatFlag explaining parameters and usage
- Add detailed docstring to setupTestCommand explaining return values
- Use constant.DefaultConversion instead of hard-coded constant.WebP for better maintainability
- Clarify when bindViper should be true vs false

Co-authored-by: Belphemur <197810+Belphemur@users.noreply.github.com>

cmd/cbzoptimizer/commands/flags.go

@@ -9,8 +9,14 @@ import (
 	"github.com/thediveo/enumflag/v2"
 )
 
-// setupFormatFlag sets up the format flag for a command
-// If bindViper is true, it will also bind the flag to viper
+// setupFormatFlag sets up the format flag for a command.
+//
+// Parameters:
+//   - cmd: The Cobra command to add the format flag to
+//   - converterType: Pointer to the ConversionFormat variable that will store the flag value
+//   - bindViper: If true, binds the flag to viper for configuration file support.
+//     Set to true for commands that use viper for configuration (e.g., watch command),
+//     and false for commands that don't (e.g., optimize command).
 func setupFormatFlag(cmd *cobra.Command, converterType *constant.ConversionFormat, bindViper bool) {
 	formatFlag := enumflag.New(converterType, "format", constant.CommandValue, enumflag.EnumCaseInsensitive)
 	_ = formatFlag.RegisterCompletion(cmd, "format", constant.HelpText)

cmd/cbzoptimizer/commands/optimize_command_test.go

@@ -173,7 +173,12 @@ func TestConvertCbzCommand(t *testing.T) {
 	t.Logf("Found %d converted files", len(convertedFiles))
 }
 
-// setupTestCommand creates a test command with all required flags
+// setupTestCommand creates a test command with all required flags for testing.
+// It mocks the converter.Get function and sets up a complete command with all flags.
+//
+// Returns:
+//   - *cobra.Command: A configured command ready for testing
+//   - func(): A cleanup function that must be deferred to restore the original converter.Get
 func setupTestCommand(t *testing.T) (*cobra.Command, func()) {
 	t.Helper()
 	
@@ -194,8 +199,8 @@ func setupTestCommand(t *testing.T) (*cobra.Command, func()) {
 	cmd.Flags().BoolP("split", "s", false, "Split long pages into smaller chunks")
 	cmd.Flags().DurationP("timeout", "t", 0, "Maximum time allowed for converting a single chapter")
 	
-	// Reset converterType to default before test
-	converterType = constant.WebP
+	// Reset converterType to default before test for consistency
+	converterType = constant.DefaultConversion
 	setupFormatFlag(cmd, &converterType, false)
 	
 	return cmd, cleanup