Add tests for jebp_utils

tests/unit/jeb_utils/test_readmsg.py

@@ -0,0 +1,44 @@
+from src.jeb_utils.jebp_utils import readmsg, _MSG_START_BYTE, MessageFormatError
+import pytest
+
+class AsyncTestStreamReader:
+    def __init__(self, content: bytes) -> None:
+        self.content = content
+
+    async def readexactly(self, n: int) -> bytes:
+        if len(self.content) < n:
+            raise EOFError
+        result = self.content[:n]
+        self.content = self.content[n:]
+        return result
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('expected,reader,start_byte', [
+    (b'', AsyncTestStreamReader(b'\x01\x01\x00'), b'\x01'),
+    (b'', AsyncTestStreamReader(b'\x02\x01\x00'), b'\x02'),
+    (b'a', AsyncTestStreamReader(b'\x02\x01\x01a'), b'\x02'),
+    (b'', AsyncTestStreamReader(b'\x01\x00'), b'\x01'),
+    (b'a' * 255, AsyncTestStreamReader(b'\x01\x01\xff' + b'a' * 255), b'\x01'),
+    (b'a' * 256, AsyncTestStreamReader(b'\x01\x02\x01\x00' + b'a' * 256), b'\x01'),
+    (b'a' * 256, AsyncTestStreamReader(b'\x01\x02\x01\x00' + b'a' * 257), b'\x01'),
+    (b'a' * 257, AsyncTestStreamReader(b'\x01\x02\x01\x01' + b'a' * 257), b'\x01'),
+])
+async def test_readmsg(expected, reader, start_byte):
+    assert await readmsg(reader, start_byte = start_byte) == expected
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('expected_exception,reader,start_byte', [
+    (EOFError, AsyncTestStreamReader(b'\x01\x01\x01'), b'\x01'),
+    (EOFError, AsyncTestStreamReader(b'\x01\x02\x01a'), b'\x01'),
+    (EOFError, AsyncTestStreamReader(b'\x01'), b'\x01'),
+    (EOFError, AsyncTestStreamReader(b'\x01\x01'), b'\x01'),
+    (EOFError, AsyncTestStreamReader(b'\x01\x02\x00'), b'\x01'),
+    (MessageFormatError, AsyncTestStreamReader(b'\x01\x02\x01a'), b'\x02'),
+    (MessageFormatError, AsyncTestStreamReader(b'\x01\x01\x01'), b'\x02'),
+    (MessageFormatError, AsyncTestStreamReader(b'\x01'), b'\x02'),
+])
+async def test_readmsg_exceptions(expected_exception, reader, start_byte):
+    with pytest.raises(expected_exception):
+        await readmsg(reader, start_byte = start_byte)