Fix tests

internal/cli/run.go

@@ -51,8 +51,6 @@ func run(o runOpts) ([]byte, error) {
 		return nil, fmt.Errorf("failed to get output writer: %w", err)
 	}
 
-	writer = parsing.MultiDocumentWriter(writer)
-
 	opts = append(opts, variableOptions(o.Vars)...)
 
 	// Default to null. If stdin is being read then this will be overwritten.

parsing/format.go

@@ -22,7 +22,11 @@ func (f Format) NewWriter(options WriterOptions) (Writer, error) {
 	if !ok {
 		return nil, fmt.Errorf("unsupported writer file format: %s", f)
 	}
-	return fn(options)
+	w, err := fn(options)
+	if err != nil {
+		return nil, err
+	}
+	return MultiDocumentWriter(w), nil
 }
 
 // String returns the string representation of the format.