1 files changed, 87 insertions, 0 deletions
diff --git a/internal/player/roomset_test.go b/internal/player/roomset_test.go
new file mode 100644
index 0000000..2b6b9cb
--- /dev/null
+++ b/internal/player/roomset_test.go
@@ -0,0 +1,87 @@
+package player
+
+import (
+	"strings"
+	"testing"
+
+	"gopkg.in/yaml.v3"
+)
+
+func TestRoomSetYAMLRoundTrip(t *testing.T) {
+	stats := PlayerStats{
+		RoomsVisited: NewRoomSetFrom(1, 5, 300),
+		MobKills:     map[string]int{"rat": 3},
+		TotalKills:   3,
+		Deaths:       0,
+	}
+	data, err := yaml.Marshal(stats)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	out := string(data)
+	if !strings.Contains(out, "rooms_visited:") {
+		t.Fatalf("expected rooms_visited key in output:\n%s", out)
+	}
+
+	var loaded PlayerStats
+	if err := yaml.Unmarshal(data, &loaded); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if loaded.RoomsVisited.Len() != 3 {
+		t.Errorf("Len = %d, want 3", loaded.RoomsVisited.Len())
+	}
+	for _, id := range []int{1, 5, 300} {
+		if !loaded.RoomsVisited.Has(id) {
+			t.Errorf("expected Has(%d) == true", id)
+		}
+	}
+	if loaded.RoomsVisited.Has(2) {
+		t.Error("expected Has(2) == false")
+	}
+}
+
+func TestRoomSetOmitEmpty(t *testing.T) {
+	stats := PlayerStats{}
+	data, err := yaml.Marshal(stats)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	out := string(data)
+	if strings.Contains(out, "rooms_visited:") {
+		t.Errorf("expected rooms_visited to be absent for empty set:\n%s", out)
+	}
+
+	var loaded PlayerStats
+	if err := yaml.Unmarshal(data, &loaded); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if loaded.RoomsVisited.Len() != 0 {
+		t.Errorf("Len = %d, want 0", loaded.RoomsVisited.Len())
+	}
+}
+
+func TestRoomSetIsZero(t *testing.T) {
+	var zero RoomSet
+	if !zero.IsZero() {
+		t.Error("zero value should be IsZero")
+	}
+	visited := NewRoomSetFrom(1)
+	if visited.IsZero() {
+		t.Error("non-empty set should not be IsZero")
+	}
+}
+
+func TestRoomSetMarshalEmpty(t *testing.T) {
+	var rs RoomSet
+	v, err := rs.MarshalYAML()
+	if err != nil {
+		t.Fatalf("MarshalYAML: %v", err)
+	}
+	s, ok := v.(string)
+	if !ok {
+		t.Fatalf("MarshalYAML returned %T, want string", v)
+	}
+	if s != "" {
+		t.Errorf("MarshalYAML empty = %q, want empty string", s)
+	}
+}