Port mtproto from grammers

client/tests/transport/intermediate_test.py

@@ -0,0 +1,45 @@
+from typing import Tuple
+
+from pytest import raises
+from telethon._impl.mtproto.transport.intermediate import Intermediate
+
+
+def setup_pack(n: int) -> Tuple[Intermediate, bytes, bytearray]:
+    input = bytes(x & 0xFF for x in range(n))
+    return Intermediate(), input, bytearray()
+
+
+def test_pack_empty() -> None:
+    transport, input, output = setup_pack(0)
+    transport.pack(input, output)
+    assert output == b"\xee\xee\xee\xee\0\0\0\0"
+
+
+def test_pack_non_padded() -> None:
+    transport, input, output = setup_pack(7)
+    with raises(AssertionError):
+        transport.pack(input, output)
+
+
+def test_pack_normal() -> None:
+    transport, input, output = setup_pack(128)
+    transport.pack(input, output)
+    assert output[:8] == b"\xee\xee\xee\xee\x80\0\0\0"
+    assert output[8:] == input
+
+
+def test_unpack_small() -> None:
+    transport = Intermediate()
+    input = b"\x01"
+    output = bytearray()
+    with raises(ValueError) as e:
+        transport.unpack(input, output)
+    e.match("missing bytes")
+
+
+def test_unpack_normal() -> None:
+    transport, input, packed = setup_pack(128)
+    unpacked = bytearray()
+    transport.pack(input, packed)
+    transport.unpack(packed[4:], unpacked)
+    assert input == unpacked