1 files changed, 78 insertions, 0 deletions
diff --git a/internal/admin/api_rooms_create_test.go b/internal/admin/api_rooms_create_test.go
new file mode 100644
index 0000000..38d6fae
--- /dev/null
+++ b/internal/admin/api_rooms_create_test.go
@@ -0,0 +1,78 @@
+package admin
+
+// Regression: a failed room create (POST /api/rooms with link_from) must
+// not leave the source room with a dangling exit pointing at a room that
+// was never written, and must not push an undo entry for work that never
+// committed. The destination is committed before the source exit so the
+// failure happens before any source-side mutation.
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"thehouseoficarus/internal/config"
+	"thehouseoficarus/internal/world"
+)
+
+func TestFailedRoomCreateRollsBackSourceExit(t *testing.T) {
+	s := newTestAdminServer(t, map[int]string{1: "id: 1\nname: Origin\n"})
+	s.cfg = config.Default()
+	s.cfg.StartingRoom = 1
+	// A directory at the destination path makes the destination file write
+	// fail deterministically while the source room is still readable.
+	if err := os.Mkdir(filepath.Join(s.dataDir, "rooms", "2.yaml"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	rec := httptest.NewRecorder()
+	s.handleRooms(rec, httptest.NewRequest(http.MethodPost, "/api/rooms",
+		strings.NewReader(`{"name":"Next","link_from":1,"link_dir":"north"}`)))
+	if !strings.Contains(rec.Body.String(), "error") {
+		t.Fatalf("expected the create to fail; got %s", rec.Body.String())
+	}
+
+	src, err := s.world.LoadRoom(1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if exit, ok := src.Exits[world.North]; ok {
+		t.Fatalf("failed create left a dangling exit to nonexistent room %d", exit.Room)
+	}
+	if info := s.undoStack.Info(); info.StackSize != 0 {
+		t.Fatalf("failed create pushed an undo entry: %+v", info)
+	}
+}
+
+// The reciprocal exit still lands in the written destination file when the
+// create succeeds.
+func TestSuccessfulRoomCreateWritesReciprocalExit(t *testing.T) {
+	s := newTestAdminServer(t, map[int]string{1: "id: 1\nname: Origin\n"})
+	s.cfg = config.Default()
+	s.cfg.StartingRoom = 1
+
+	rec := httptest.NewRecorder()
+	s.handleRooms(rec, httptest.NewRequest(http.MethodPost, "/api/rooms",
+		strings.NewReader(`{"name":"Next","link_from":1,"link_dir":"north"}`)))
+	if strings.Contains(rec.Body.String(), "error") {
+		t.Fatalf("create failed: %s", rec.Body.String())
+	}
+
+	dest, err := s.world.LoadRoom(2)
+	if err != nil {
+		t.Fatalf("destination room not loadable: %v", err)
+	}
+	if dest.Exits[world.South].Room != 1 {
+		t.Fatalf("destination room missing its reciprocal exit south: %+v", dest.Exits)
+	}
+	src, err := s.world.LoadRoom(1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if src.Exits[world.North].Room != 2 {
+		t.Fatalf("source room missing its north exit: %+v", src.Exits)
+	}
+}