fix connection trough tunnel (#36). (#37)

* fix connection trough tunnel (#36).

* move 'open' tunnel to a dedicated method.

* update test statement.

pylink/jlink.py

@@ -544,7 +544,7 @@ def open(self, serial_no=None, ip_addr=None):
         self.close()
 
         if ip_addr is not None:
-            addr, port = ip_addr.split(':')
+            addr, port = ip_addr.rsplit(':', 1)
             if serial_no is None:
                 result = self._dll.JLINKARM_SelectIP(addr.encode(), int(port))
                 if result == 1:
@@ -590,6 +590,19 @@ def open(self, serial_no=None, ip_addr=None):
 
         return None
 
+    def open_tunnel(self, serial_no, port=19020):
+        """Connects to the J-Link emulator (over SEGGER tunnel).
+
+        Args:
+          self (JLink): the ``JLink`` instance
+          serial_no (int): serial number of the J-Link
+          port (int): optional port number (default to 19020).
+
+        Returns:
+          ``None``
+        """
+        return self.open(ip_addr='tunnel:' + str(serial_no) + ':' + str(port))
+
     def close(self):
         """Closes the open J-Link.
 

tests/unit/test_jlink.py

@@ -610,6 +610,24 @@ def test_jlink_open_ethernet_and_serial_number(self):
         self.assertEqual(0, self.dll.JLINKARM_EMU_SelectIP.call_count)
         self.assertEqual(1, self.dll.JLINKARM_EMU_SelectIPBySN.call_count)
 
+    def test_jlink_open_tunnel(self):
+        """Tests the J-Link ``open_tunnel()`` method over tunnel succeeding
+        with default port value.
+
+        Args:
+          self (TestJLink): the ``TestJLink`` instance
+
+        Returns:
+          ``None``
+        """
+        self.dll.JLNKARM_SelectIP.return_value = 0
+        self.dll.JLINKARM_OpenEx.return_value = 0
+        self.dll.JLINKARM_GetSN.return_value = 123456789
+
+        self.jlink.open_tunnel(serial_no=123456789)
+
+        self.dll.JLINKARM_SelectIP.assert_called_once_with('tunnel:123456789'.encode(), 19020)
+
     def test_jlink_open_serial_number_failed(self):
         """Tests the J-Link ``open()`` method over USB by serial number, but
         failing.