From a7eff0af144b081a59cddf8e1c612a562e3868d5 Mon Sep 17 00:00:00 2001
From: Ruben Vandamme <github-com-00ff86@vandamme.email>
Date: Mon, 6 May 2024 17:29:41 +0000
Subject: [PATCH] Improve read_byte retry mechanism #8

---
 comfospot40/parser.py | 10 ++++++--
 tests/parser_test.py  | 55 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 tests/parser_test.py

diff --git a/comfospot40/parser.py b/comfospot40/parser.py
index dde620c..c20aba7 100644
--- a/comfospot40/parser.py
+++ b/comfospot40/parser.py
@@ -5,6 +5,7 @@
 import copy
 from datetime import datetime
 from serial import SerialException
+import asyncio
 
 
 class Parser:
@@ -19,12 +20,17 @@ def __init__(self, serial, packetlog=None, state=State()):
     def get_state(self):
         return self._state
 
-    async def read_byte(self):
+    async def read_byte(self, retries=5):
         while True:
             try:
                 return await self._ser.read(1)
             except SerialException as e:
-                logging.warn("Failed to read serial", e)
+                logging.warning("Failed to read serial: {}".format(e))
+                if retries > 0:
+                    await asyncio.sleep(0.1 * retries)
+                    retries -= 1
+                else:
+                    raise e
 
     async def search_length(self, data):
         logging.info("z")
diff --git a/tests/parser_test.py b/tests/parser_test.py
new file mode 100644
index 0000000..67ab3e1
--- /dev/null
+++ b/tests/parser_test.py
@@ -0,0 +1,55 @@
+import asyncio
+import unittest
+import comfospot40
+import logging
+from serial import SerialException
+
+
+class TestStateLoad(unittest.IsolatedAsyncioTestCase):
+    async def test_read_byte_ok(self):
+        class TestSerial:
+            async def read(self, _):
+                return b"A"
+
+        s = TestSerial()
+        p = comfospot40.Parser(s)
+        self.assertEqual(b"A", await p.read_byte())
+
+    async def test_read_byte_error(self):
+        logging.disable(logging.CRITICAL)
+
+        class TestSerial:
+            async def read(self, _):
+                raise SerialException("something")
+                return b"A"
+
+        s = TestSerial()
+        p = comfospot40.Parser(s)
+        with self.assertRaises(SerialException):
+            await p.read_byte(0)
+
+    async def test_read_byte_retry(self):
+        logging.disable(logging.CRITICAL)
+
+        class TestSerial:
+            async def read(self, _):
+                raise SerialException("something")
+                return b"A"
+
+        s = TestSerial()
+        p = comfospot40.Parser(s)
+        with self.assertRaises(SerialException):
+            await asyncio.wait_for(p.read_byte(0), timeout=1)
+
+    async def test_read_byte_retry_timeout(self):
+        logging.disable(logging.CRITICAL)
+
+        class TestSerial:
+            async def read(self, _):
+                raise SerialException("something")
+                return b"A"
+
+        s = TestSerial()
+        p = comfospot40.Parser(s)
+        with self.assertRaises(asyncio.exceptions.TimeoutError):
+            await asyncio.wait_for(p.read_byte(2), timeout=0.1)