Update diagnostics/os_diagnostics.py

diagnostics/os_diagnostics.py

@@ -1,5 +1,29 @@
 from pybricks.parameters import Port
 from uerrno import EAGAIN, EBUSY, ECANCELED, EINVAL, EIO, ENODEV, EOPNOTSUPP, EPERM, ETIMEDOUT
+from pybricks.iodevices import UARTDevice as _UARTDevice
+from pybricks.tools import wait
+
+class FakeUART:
+    def __init__(self, port, baudrate, timeout):
+        self.timeout = timeout
+        print("Warning: No physical UART detected. Using simulator.")
+
+    def read(self, length=1):
+        if self.timeout is not None:
+            wait(self.timeout)
+            raise OSError(ETIMEDOUT)
+        else:
+            while True:
+                wait(1000)
+
+    def write(self, data):
+        pass
+
+def UARTDevice(port, baudrate=9600, timeout=None):
+    try:
+        return _UARTDevice(port, baudrate, timeout)
+    except OSError:
+        return FakeUART(port, baudrate, timeout)
 class OSDiagnostics:
     def __init__(self, hub, motorclass):
         self.motorclass = motorclass
@@ -23,6 +47,21 @@ class OSDiagnostics:
             else:
                 print(f"Another error occurred with code: {ex.errno}.\nCompleted Test 6/9: ENODEV - FAILED")
                 self.failedtests["ENODEV"] = ex.errno
+    def testetimedout(self):
+        uart = UARTDevice(Port.A, baudrate=9600, timeout=1000)  # 1000ms timeout
+        # Test ETIMEDOUT
+        try:
+            data = uart.read(10)  # FakeUART will wait `timeout` ms, then raise OSError(ETIMEDOUT)
+        except OSError as ex:
+            if ex.errno == ETIMEDOUT:
+                print("Timed out with synthetic UART device. ETIMEDOUT can be thrown and caught.\nCompleted Test 9/9: ETIMEDOUT - SUCCESSFUL")
+                self.successfultests += 1
+            elif ex.errno == EIO:
+                print("An unspecified error occurred (EIO).\nCompleted Test 9/9: ETIMEDOUT - FAILED")
+                self.failedtests["ETIMEDOUT"] = "EIO - Unspecified Error"
+            else:
+                print(f"Another error occurred with code: {ex.errno}.\nCompleted Test 9/9: ETIMEDOUT - FAILED")
+                self.failedtests["ETIMEDOUT"] = ex.errno
     def print_results(self):
         for key, value in self.failedtests():
             print(f"{key}: {value}")