Added round-trip test for bytestrings (#210)

tests/test_decoder.py

@@ -17,6 +17,8 @@
 from uuid import UUID
 
 import pytest
+from hypothesis import example, given
+from hypothesis.strategies import binary
 
 from cbor2 import FrozenDict
 
@@ -222,6 +224,12 @@ def test_binary(impl, payload, expected):
     assert decoded == expected
 
 
+@given(binary(min_size=2**6, max_size=2**20))
+@example(b"\x12" * 65537)  # anything over 2**16 fails in C
+def test_binary_roundtrip(impl, expected):
+    assert expected == impl.loads(impl.dumps(expected)), "Binary string fails to round-trip"
+
+
 @pytest.mark.parametrize(
     "payload, expected",
     [