feat(state): persist per-run logs with rotation and last-run pointer

internal/state/state_test.go

@@ -0,0 +1,63 @@
+package state
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func newStore(t *testing.T) *Store {
+	t.Helper()
+	return &Store{Root: t.TempDir()}
+}
+
+func TestSaveAndLoadLast(t *testing.T) {
+	s := newStore(t)
+	rec := RunRecord{
+		StartedAt: time.Date(2026, 4, 13, 10, 0, 0, 0, time.UTC),
+		EndedAt:   time.Date(2026, 4, 13, 10, 1, 0, 0, time.UTC),
+		Modules:   []ModuleRecord{{ID: "hello", Status: "succeeded", Duration: "1s"}},
+	}
+	if err := s.Save(rec, 10); err != nil {
+		t.Fatal(err)
+	}
+	got, ok, err := s.LastRun()
+	if err != nil || !ok {
+		t.Fatalf("LastRun err=%v ok=%v", err, ok)
+	}
+	if len(got.Modules) != 1 || got.Modules[0].ID != "hello" {
+		t.Fatalf("modules = %+v", got.Modules)
+	}
+}
+
+func TestLastRunMissingReturnsFalse(t *testing.T) {
+	s := newStore(t)
+	_, ok, err := s.LastRun()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if ok {
+		t.Fatal("expected ok=false")
+	}
+}
+
+func TestRotateKeepsNewest(t *testing.T) {
+	s := newStore(t)
+	for i := 0; i < 12; i++ {
+		rec := RunRecord{
+			StartedAt: time.Date(2026, 1, 1, 0, 0, i, 0, time.UTC),
+			EndedAt:   time.Date(2026, 1, 1, 0, 0, i, 0, time.UTC),
+		}
+		if err := s.Save(rec, 5); err != nil {
+			t.Fatal(err)
+		}
+	}
+	entries, err := os.ReadDir(filepath.Join(s.Root, "runs"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(entries) != 5 {
+		t.Fatalf("runs count = %d, want 5", len(entries))
+	}
+}