Add graph_test into testcases

Author: YanWQ-monad

cyaron/tests/__init__.py

@@ -2,4 +2,5 @@
 from .io_test import TestIO
 from .str_test import TestString
 from .polygon_test import TestPolygon
-from .compare_test import TestCompare
+from .compare_test import TestCompare
+from .graph_test import TestGraph