Added initial tests and some small fixes and improvements.

hpib.py

@@ -17,10 +17,16 @@ class PROLOGIX_GPIB_USB():
                 port = "/dev/ttys000"
                 portFormat = "%03d"
                 maxDeviceNum = 999
+            else:
+                raise NotImplementedError("Windows is not supported")
         if verbose:
             print "Looking for ports such as %s in range %d on %s" % \
                   ( port, maxDeviceNum, platform.system() )
         self._rematch=re.search(r"(/dev/tty.*[^0-9])([0-9]+$)",port)
+
+        if not self._rematch:
+            raise ValueError(port)
+
         self._serialPort = None
         while int(self._rematch.group(2)) < maxDeviceNum:
             if verbose:
@@ -32,7 +38,7 @@ class PROLOGIX_GPIB_USB():
                 port=self._rematch.group(1) +\
                       (portFormat % (int(self._rematch.group(2))+1))
                 self._rematch=re.search("(/dev/tty.*[^0-9])([0-9]+$)",port)
-        if port==None:
+        if self._serialPort==None:
             raise serial.SerialException("Cannot find port")
         self._serialPort.write("++savecfg 0"       + chr(10))
         self._serialPort.write("++auto 0"          + chr(10))

test/test_hpib.py

+import hpib
+import unittest
+from mock import patch, call
+from serial import SerialException
+
+
+class PrologixGpibUsbTest(unittest.TestCase):
+    def setUp(self):
+        serial_patcher = patch('hpib.serial.Serial')
+        self.serial_mock = serial_patcher.start()
+        self.addCleanup(serial_patcher.stop)
+
+        platform_pathcer = patch('hpib.platform')
+        self.platform_mock = platform_pathcer.start()
+        self.addCleanup(platform_pathcer.stop)
+
+        self.platform_mock.system.return_value = "Linux"
+
+    def test_when_platform_linux_port_gets_set_to_ttyusb0(self):
+        hpib.PROLOGIX_GPIB_USB()
+
+        self.serial_mock.assert_called_with('/dev/ttyUSB0', timeout=1)
+
+    def test_when_platform_darwin_port_gets_set_to_ttys000(self):
+        self.platform_mock.system.return_value = "Darwin"
+
+        hpib.PROLOGIX_GPIB_USB()
+
+        self.serial_mock.assert_called_with('/dev/ttys000', timeout=1)
+
+    def test_getDevices_returns_not_scanned_when_find_devices_is_false(self):
+        usb = hpib.PROLOGIX_GPIB_USB(findDevices=False)
+
+        self.assertEqual(usb.getDevices(), 'Not scanned.')
+
+    def test_raises_serial_exception_when_all_serial_ports_fail(self):
+        self.serial_mock.side_effect = SerialException
+
+        with self.assertRaises(SerialException):
+            hpib.PROLOGIX_GPIB_USB()
+
+    def test_when_platform_linux_last_port_tried_is_ttyusb98(self):
+        self.serial_mock.side_effect = SerialException
+
+        with self.assertRaises(SerialException):
+            hpib.PROLOGIX_GPIB_USB()
+
+        self.serial_mock.assert_called_with('/dev/ttyUSB98', timeout=1)
+
+    def test_when_platform_darwin_last_port_tried_is_ttyusb98(self):
+        self.platform_mock.system.return_value = "Darwin"
+        self.serial_mock.side_effect = SerialException
+
+        with self.assertRaises(SerialException):
+            hpib.PROLOGIX_GPIB_USB()
+
+        self.serial_mock.assert_called_with('/dev/ttys998', timeout=1)
+
+    def test_setup_device_when_port_found(self):
+        write_mock = self.serial_mock.return_value.write
+
+        hpib.PROLOGIX_GPIB_USB()
+
+        self.assertEqual(write_mock.call_args_list[0], call("++savecfg 0" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[1], call("++auto 0" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[2], call("++eoi 1" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[3], call("++eos 2" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[4], call("++eot_enable 0" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[5], call("++eot_char 0" + chr(10)))
+        self.assertEqual(write_mock.call_args_list[6], call("++read_tmo_ms 500" + chr(10)))
+
+    def test_setup_calls_identify_command_when_finding_devices(self):
+        self.serial_mock.return_value.readline.return_value = ""
+        write_mock = self.serial_mock.return_value.write
+
+        hpib.PROLOGIX_GPIB_USB(findDevices=True)
+
+        self.assertEqual(write_mock.call_args_list[7],
+                         call("++addr " + str(0) + chr(10) + "*idn?" + chr(10) + "++read" + chr(10)))
+
+    def test_if_find_devices_getDevices_will_return_a_list_of_devices(self):
+        self.serial_mock.return_value.readline.return_value = "Device 1"
+        usb = hpib.PROLOGIX_GPIB_USB(findDevices=True)
+
+        devices = usb.getDevices()
+
+        self.assertEqual(len(devices), 2 * 31)
+        self.assertEqual(devices[0], 0)
+        self.assertEqual(devices[1], "Device 1")
+
+    def test_if_platform_windows_and_not_port_defined_raises_not_implemented_exception(self):
+        self.platform_mock.system.return_value = "Windows"
+
+        with self.assertRaises(NotImplementedError):
+            hpib.PROLOGIX_GPIB_USB()
+
+    def test_if_given_port_does_not_start_with_dev_tty_an_exception_is_raised(self):
+        with self.assertRaises(ValueError):
+            hpib.PROLOGIX_GPIB_USB(port="device")
+
+if __name__ == '__main__':
+    unittest.main()