SETUP move code to src

This way we can ensure that the packaged code is tested.
See https://hynek.me/articles/testing-packaging/ or c62a78c015

+ DOC adapt doc to new structure and test doc with travis

src/escpos/exceptions.py

@@ -0,0 +1,241 @@
+#  -*- coding: utf-8 -*-
+""" ESC/POS Exceptions classes
+
+Result/Exit codes:
+
+    - `0`  = success
+    - `10` = No Barcode type defined :py:exc:`~escpos.exceptions.BarcodeTypeError`
+    - `20` = Barcode size values are out of range :py:exc:`~escpos.exceptions.BarcodeSizeError`
+    - `30` = Barcode text not supplied :py:exc:`~escpos.exceptions.BarcodeCodeError`
+    - `40` = Image height is too large :py:exc:`~escpos.exceptions.ImageSizeError`
+    - `50` = No string supplied to be printed :py:exc:`~escpos.exceptions.TextError`
+    - `60` = Invalid pin to send Cash Drawer pulse :py:exc:`~escpos.exceptions.CashDrawerError`
+    - `70` = Invalid number of tab positions :py:exc:`~escpos.exceptions.TabPosError`
+    - `80` = Invalid char code :py:exc:`~escpos.exceptions.CharCodeError`
+    - `90` = USB device not found :py:exc:`~escpos.exceptions.USBNotFoundError`
+    - `100` = Set variable out of range :py:exc:`~escpos.exceptions.SetVariableError`
+    - `200` = Configuration not found :py:exc:`~escpos.exceptions.ConfigNotFoundError`
+    - `210` = Configuration syntax error :py:exc:`~escpos.exceptions.ConfigSyntaxError`
+    - `220` = Configuration section not found :py:exc:`~escpos.exceptions.ConfigSectionMissingError`
+
+:author: `Manuel F Martinez <manpaz@bashlinux.com>`_ and others
+:organization: Bashlinux and `python-escpos <https://github.com/python-escpos>`_
+:copyright: Copyright (c) 2012 Bashlinux
+:license: GNU GPL v3
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+
+class Error(Exception):
+    """ Base class for ESC/POS errors """
+    def __init__(self, msg, status=None):
+        Exception.__init__(self)
+        self.msg = msg
+        self.resultcode = 1
+        if status is not None:
+            self.resultcode = status
+
+    def __str__(self):
+        return self.msg
+
+
+class BarcodeTypeError(Error):
+    """ No Barcode type defined.
+
+    This exception indicates that no known barcode-type has been entered. The barcode-type has to be
+    one of those specified in :py:meth:`escpos.escpos.Escpos.barcode`.
+    The returned error code is `10`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 10
+
+    def __str__(self):
+        return "No Barcode type is defined ({msg})".format(msg=self.msg)
+
+
+class BarcodeSizeError(Error):
+    """ Barcode size is out of range.
+
+    This exception indicates that the values for the barcode size are out of range.
+    The size of the barcode has to be in the range that is specified in :py:meth:`escpos.escpos.Escpos.barcode`.
+    The resulting returncode is `20`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 20
+
+    def __str__(self):
+        return "Barcode size is out of range ({msg})".format(msg=self.msg)
+
+
+class BarcodeCodeError(Error):
+    """ No Barcode code was supplied.
+
+    No data for the barcode has been supplied in :py:meth:`escpos.escpos.Escpos.barcode`.
+    The returncode for this exception is `30`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 30
+
+    def __str__(self):
+        return "No Barcode code was supplied"
+
+
+class ImageSizeError(Error):
+    """ Image height is longer than 255px and can't be printed.
+
+    The returncode for this exception is `40`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 40
+
+    def __str__(self):
+        return "Image height is longer than 255px and can't be printed"
+
+
+class TextError(Error):
+    """ Text string must be supplied to the `text()` method.
+
+    This exception is raised when an empty string is passed to :py:meth:`escpos.escpos.Escpos.text`.
+    The returncode for this exception is `50`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 50
+
+    def __str__(self):
+        return "Text string must be supplied to the text() method"
+
+
+class CashDrawerError(Error):
+    """ Valid pin must be set in order to send pulse.
+
+    A valid pin number has to be passed onto the method :py:meth:`escpos.escpos.Escpos.cashdraw`.
+    The returncode for this exception is `60`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 60
+
+    def __str__(self):
+        return "Valid pin must be set to send pulse"
+
+
+class TabPosError(Error):
+    """ Valid tab positions must be in the range 0 to 16.
+
+    This exception is raised by :py:meth:`escpos.escpos.Escpos.control`.
+    The returncode for this exception is `70`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 70
+
+    def __str__(self):
+        return "Valid tab positions must be in the range 0 to 16"
+
+
+class CharCodeError(Error):
+    """ Valid char code must be set.
+
+    The supplied charcode-name in :py:meth:`escpos.escpos.Escpos.charcode` is unknown.
+    Ths returncode for this exception is `80`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 80
+
+    def __str__(self):
+        return "Valid char code must be set"
+
+
+class USBNotFoundError(Error):
+    """ Device wasn't found (probably not plugged in)
+
+    The USB device seems to be not plugged in.
+    Ths returncode for this exception is `90`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 90
+
+    def __str__(self):
+        return "USB device not found"
+
+
+class SetVariableError(Error):
+    """ A set method variable was out of range
+
+    Check set variables against minimum and maximum values
+    Ths returncode for this exception is `100`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 100
+
+    def __str__(self):
+        return "Set variable out of range"
+
+
+# Configuration errors
+
+class ConfigNotFoundError(Error):
+    """ The configuration file was not found
+
+    The default or passed configuration file could not be read
+    Ths returncode for this exception is `200`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 200
+
+    def __str__(self):
+        return "Configuration not found ({msg})".format(msg=self.msg)
+
+
+class ConfigSyntaxError(Error):
+    """ The configuration file is invalid
+
+    The syntax is incorrect
+    Ths returncode for this exception is `210`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 210
+
+    def __str__(self):
+        return "Configuration syntax is invalid ({msg})".format(msg=self.msg)
+
+
+class ConfigSectionMissingError(Error):
+    """ The configuration file is missing a section
+
+    The part of the config asked for doesn't exist in the loaded configuration
+    Ths returncode for this exception is `220`.
+    """
+    def __init__(self, msg=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 220
+
+    def __str__(self):
+        return "Configuration section is missing ({msg})".format(msg=self.msg)