From 54b65088f7eb7187ade9753a1beb0c4183636f67 Mon Sep 17 00:00:00 2001
From: TJ Bruno <tj.bruno@everactive.com>
Date: Wed, 25 Jan 2023 16:05:52 -0800
Subject: [PATCH 1/2] Add unittest

---
 test/test_slcan.py | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/test/test_slcan.py b/test/test_slcan.py
index aa97e518b..bd0d8deb9 100644
--- a/test/test_slcan.py
+++ b/test/test_slcan.py
@@ -1,6 +1,13 @@
 #!/usr/bin/env python
 
+import os
+import threading
+import time
 import unittest
+from platform import platform
+
+import pytest
+
 import can
 
 
@@ -123,5 +130,55 @@ def test_serial_number(self):
         self.assertIsNone(sn)
 
 
+@pytest.fixture
+def pseudo_terminal():
+    import pty
+
+    main, peripheral = pty.openpty()
+
+    return main, peripheral
+
+
+@pytest.fixture
+def bus(pseudo_terminal):
+    _, peripheral = pseudo_terminal
+    return can.Bus(os.ttyname(peripheral), interface="slcan", sleep_after_open=0)
+
+
+@pytest.fixture
+def bus_writer(pseudo_terminal):
+    main, _ = pseudo_terminal
+    writer = os.fdopen(main, "wb")
+    return writer
+
+
+@pytest.mark.skipif("linux" not in platform().lower(), reason="Requires Linux")
+@pytest.mark.parametrize("timeout", [0.5, 1])
+def test_verify_recv_timeout(timeout, bus, bus_writer):
+    msg = b"Hello"
+    unterminated = msg
+    terminated = msg + b"\r"
+
+    def consecutive_writes():
+        bus_writer.write(terminated)
+        bus_writer.flush()
+        time.sleep(timeout / 2)
+        bus_writer.write(unterminated)
+        bus_writer.flush()
+
+    timeout_ms = int(timeout * 1_000)
+    allowable_timeout_error = timeout_ms / 200
+
+    writer_thread = threading.Thread(target=consecutive_writes)
+
+    start_time = time.time_ns()
+    writer_thread.start()
+    bus.recv(timeout)
+    stop_time = time.time_ns()
+
+    duration_ms = int((stop_time - start_time) / 1_000_000)
+    assert duration_ms - timeout_ms < allowable_timeout_error
+
+
 if __name__ == "__main__":
     unittest.main()

From a57e2a556122f2cc5a74d74989d9bb67c787d484 Mon Sep 17 00:00:00 2001
From: TJ Bruno <tj.bruno@everactive.com>
Date: Thu, 26 Jan 2023 08:32:19 -0800
Subject: [PATCH 2/2] Improve test logic

---
 test/test_slcan.py | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/test/test_slcan.py b/test/test_slcan.py
index bd0d8deb9..c38848373 100644
--- a/test/test_slcan.py
+++ b/test/test_slcan.py
@@ -148,28 +148,32 @@ def bus(pseudo_terminal):
 @pytest.fixture
 def bus_writer(pseudo_terminal):
     main, _ = pseudo_terminal
-    writer = os.fdopen(main, "wb")
-    return writer
+    return os.fdopen(main, "wb")
 
 
 @pytest.mark.skipif("linux" not in platform().lower(), reason="Requires Linux")
 @pytest.mark.parametrize("timeout", [0.5, 1])
 def test_verify_recv_timeout(timeout, bus, bus_writer):
-    msg = b"Hello"
-    unterminated = msg
-    terminated = msg + b"\r"
 
-    def consecutive_writes():
-        bus_writer.write(terminated)
+    # Recv timeout should always occur
+    # since the message is not delimited
+    msg = b"F00B4R"
+
+    def delayed_consecutive_writes():
+        bus_writer.write(msg)
         bus_writer.flush()
-        time.sleep(timeout / 2)
-        bus_writer.write(unterminated)
+
+        # Delay until we're close to the end of
+        # timeout before sending another message
+        time.sleep(timeout * 0.75)
+
+        bus_writer.write(msg)
         bus_writer.flush()
 
     timeout_ms = int(timeout * 1_000)
     allowable_timeout_error = timeout_ms / 200
 
-    writer_thread = threading.Thread(target=consecutive_writes)
+    writer_thread = threading.Thread(target=delayed_consecutive_writes)
 
     start_time = time.time_ns()
     writer_thread.start()