diff --git a/.gitignore b/.gitignore
index ba04aac..b8fd992 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,6 @@
 /xmodem.egg-info
 /.coverage
 /.tox
+/.cache
+/.idea
 *.py.swp
diff --git a/test/unit/test_xmodem.py b/test/unit/test_xmodem.py
index 3b724d5..8127bbd 100644
--- a/test/unit/test_xmodem.py
+++ b/test/unit/test_xmodem.py
@@ -7,10 +7,13 @@
     from io import BytesIO
 except ImportError:
     # python 2
-    import StringIO.StringIO as BytesIO
+    from StringIO import StringIO as BytesIO
 
 # local
-import xmodem
+from xmodem import NAK
+from xmodem import CRC
+from xmodem import ACK
+from xmodem import XMODEM
 
 # 3rd-party
 import pytest
@@ -24,24 +27,95 @@ def dummy_putc(data, timeout=1):
     return 0
 
 
+def test_xmodem_bad_mode():
+    # given,
+    mode = 'XXX'
+    modem = XMODEM(getc=dummy_getc, putc=dummy_putc, mode=mode)
+    # exercise
+    with pytest.raises(ValueError):
+        status = modem.send(BytesIO(b'dummy-stream'))
+
+
 @pytest.mark.parametrize('mode', ['xmodem', 'xmodem1k'])
 def test_xmodem_dummy_fails_send(mode):
     # given,
-    modem = xmodem.XMODEM(getc=dummy_getc,
-                          putc=dummy_putc,
-                          mode=mode)
+    modem = XMODEM(getc=dummy_getc, putc=dummy_putc, mode=mode)
     # exercise
     status = modem.send(BytesIO(b'dummy-stream'))
     # verify
     assert not status, ("Expected value of status `False'")
 
 
-def test_xmodem_bad_mode():
+@pytest.mark.parametrize('mode', ['xmodem', 'xmodem1k'])
+@pytest.mark.parametrize('stream_data', [BytesIO(b'dummy-stream ' * 17),
+                                         BytesIO(b'dummy-stream ' * 1000)])
+def test_xmodem_send_exceed_maximum_number_of_resend(mode, stream_data):
+    """ XMODEM has retry parameter this function ensure that xmodem.send() will
+    return False dude to the fact that resend exceeded """
     # given,
-    mode = 'XXX'
-    modem = xmodem.XMODEM(getc=dummy_getc,
-                          putc=dummy_putc,
-                          mode=mode)
+    max_resend = 16
+
+    def generator():
+        if mode == 'xmodem':
+            yield NAK
+        else:
+            yield CRC
+
+        if mode == 'xmodem':
+            yield ACK
+
+        for i in range(max_resend + 1):
+            yield None
+
+        while True:
+            yield ACK
+
+    mock = generator()
+
+    def mock_getc(size, timeout=1):
+        try:
+            # python 2
+            x = mock.next()
+        except AttributeError:
+            # python 3
+            x = next(mock)
+        return x
+
+    xmodem = XMODEM(getc=mock_getc, putc=dummy_putc, mode=mode)
     # exercise
-    with pytest.raises(ValueError):
-        status = modem.send(BytesIO(b'dummy-stream'))
+    assert not xmodem.send(stream=stream_data, retry=max_resend)
+
+
+@pytest.mark.parametrize('mode', ['xmodem', 'xmodem1k'])
+@pytest.mark.parametrize('stream_data', [BytesIO(b'dummy-stream ' * 17),
+                                         BytesIO(b'dummy-stream ' * 1000)])
+def test_xmodem_send_fails_once_each_packet(mode, stream_data):
+    """ XMODEM has retry parameter this test ensure that the number of retry for
+     the whole stream_data will be higher the max_resend pro packet """
+    # given,
+    max_resend = 16
+
+    def generator():
+        if mode == 'xmodem':
+            yield NAK
+        else:
+            yield CRC
+
+        while True:
+            yield None
+            yield ACK
+
+    mock = generator()
+
+    def mock_getc(size, timeout=1):
+        try:
+            # python 2
+            x = mock.next()
+        except AttributeError:
+            # python 3
+            x = next(mock)
+        return x
+
+    xmodem = XMODEM(getc=mock_getc, putc=dummy_putc, mode=mode)
+    # exercise
+    assert xmodem.send(stream=stream_data, retry=max_resend)
diff --git a/xmodem/__init__.py b/xmodem/__init__.py
index 0ed7500..0fa231e 100644
--- a/xmodem/__init__.py
+++ b/xmodem/__init__.py
@@ -210,7 +210,7 @@ def send(self, stream, retry=16, timeout=60, quiet=False, callback=None):
         '''
         Send a stream via the XMODEM protocol.
 
-            >>> stream = file('/etc/issue', 'rb')
+            >>> stream = open('/etc/issue', 'rb')
             >>> print(modem.send(stream))
             True
 
@@ -308,6 +308,7 @@ def callback(total_packets, success_count, error_count)
                     success_count += 1
                     if callable(callback):
                         callback(total_packets, success_count, error_count)
+                    error_count = 0
                     break
 
                 self.log.error('send error: expected ACK; got %r for block %d',
@@ -370,7 +371,7 @@ def recv(self, stream, crc_mode=1, retry=16, timeout=60, delay=1, quiet=0):
         '''
         Receive a stream via the XMODEM protocol.
 
-            >>> stream = file('/etc/issue', 'wb')
+            >>> stream = open('/etc/issue', 'wb')
             >>> print(modem.recv(stream))
             2342