Fix styled switch-back repaint

internal/harness/runner.go

@@ -3,6 +3,7 @@ package harness
 import (
 	"encoding/json"
 	"fmt"
+	"regexp"
 	"strings"
 )
 
@@ -74,6 +75,43 @@ func runStep(s *Session, step Step, results map[string]json.RawMessage) error {
 			return fmt.Errorf("screen does not contain %q:\n%s", step.Contains, screen)
 		}
 		return nil
+	case "assert_not_contains":
+		screen, err := s.Screen()
+		if err != nil {
+			return err
+		}
+		if strings.Contains(screen, step.Contains) {
+			return fmt.Errorf("screen contains %q:\n%s", step.Contains, screen)
+		}
+		return nil
+	case "mark_raw":
+		if step.SaveAs == "" {
+			return fmt.Errorf("mark_raw requires save_as")
+		}
+		raw, err := json.Marshal(s.RawOffset())
+		if err != nil {
+			return err
+		}
+		results[step.SaveAs] = raw
+		return nil
+	case "assert_raw_since_regex":
+		raw, ok := results[step.From]
+		if !ok {
+			return fmt.Errorf("no saved result %q", step.From)
+		}
+		var offset int
+		if err := json.Unmarshal(raw, &offset); err != nil {
+			return fmt.Errorf("saved result %q is not a raw offset: %w", step.From, err)
+		}
+		re, err := regexp.Compile(step.Regex)
+		if err != nil {
+			return err
+		}
+		b := s.RawSince(offset)
+		if !re.Match(b) {
+			return fmt.Errorf("raw output since %q does not match %q:\n%s", step.From, step.Regex, string(b))
+		}
+		return nil
 	case "assert_regex":
 		return s.WaitForRegex(step.Regex, timeoutMS(step.TimeoutMS))
 	case "wait_text":