1 files changed, 26 insertions, 0 deletions
diff --git a/internal/controlplane/usage_test.go b/internal/controlplane/usage_test.go
new file mode 100644
index 0000000..d47ce16
--- /dev/null
+++ b/internal/controlplane/usage_test.go
@@ -0,0 +1,26 @@
+package controlplane
+
+import (
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestUsageCursorRoundTrip(t *testing.T) {
+	record := UsageRecord{RequestID: "req_cursor_test", StartedAt: time.Date(2026, 8, 6, 2, 3, 4, 567, time.UTC)}
+	cursor, err := decodeUsageCursor(encodeUsageCursor(record))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cursor.RequestID != record.RequestID || !cursor.StartedAt.Equal(record.StartedAt) {
+		t.Fatalf("cursor = %+v, want request %s at %v", cursor, record.RequestID, record.StartedAt)
+	}
+}
+
+func TestUsageCursorRejectsInvalidInput(t *testing.T) {
+	for _, raw := range []string{"not-base64!", "e30", string(make([]byte, 2049))} {
+		if _, err := decodeUsageCursor(raw); !errors.Is(err, ErrInvalidUsageCursor) {
+			t.Fatalf("decodeUsageCursor(%q) error = %v", raw, err)
+		}
+	}
+}