Make flag mutually exclusive

util/cli_test.go

@@ -0,0 +1,52 @@
+package util
+
+import (
+	"context"
+	"testing"
+
+	"github.com/urfave/cli/v3"
+)
+
+func runWithArgs(args []string) error {
+	cmd := &cli.Command{
+		Flags: []cli.Flag{
+			&cli.BoolFlag{Name: "title-from-h1"},
+			&cli.BoolFlag{Name: "title-from-filename"},
+		},
+		Before: CheckMutuallyExclusiveTitleFlags,
+		Action: func(ctx context.Context, cmd *cli.Command) error {
+			return nil
+		},
+	}
+	return cmd.Run(context.Background(), args)
+}
+
+func TestCheckMutuallyExclusiveTitleFlags(t *testing.T) {
+	t.Run("neither flag set", func(t *testing.T) {
+		err := runWithArgs([]string{"cmd"})
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+	})
+
+	t.Run("only title-from-h1 set", func(t *testing.T) {
+		err := runWithArgs([]string{"cmd", "--title-from-h1"})
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+	})
+
+	t.Run("only title-from-filename set", func(t *testing.T) {
+		err := runWithArgs([]string{"cmd", "--title-from-filename"})
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+	})
+
+	t.Run("both flags set", func(t *testing.T) {
+		err := runWithArgs([]string{"cmd", "--title-from-h1", "--title-from-filename"})
+		if err == nil {
+			t.Errorf("expected error, got nil")
+		}
+	})
+}