Merge #486

486: Python 2 drop and tests improvement r=MatthieuDartiailh a=MatthieuDartiailh

With the new year it is time to drop Python 2. 

Also thanks to the generous support of Keysight, PyVISA developers can have access to a virtual instrument software allowing to test more thoroughly PyVISA. As a consequence the testsuite has been vastly increased and now cover much more code even without Keysight software installed. Hopefully this will help speed up the development of PyVISA. 

As a follow-up to this PR, I will try to introduce the use of Black to format the codebase and add type hints.

Co-authored-by: MatthieuDartiailh <marul@laposte.net>
Co-authored-by: mdartiailh <m.dartiailh@gmail.com>

.coveragerc

@@ -0,0 +1,17 @@
+[run]
+branch = True
+include =
+    */pyvisa/*
+omit =
+    */pyvisa/testsuite/*
+    */pyvisa/thirdparty/*
+
+[report]
+# Regexes for lines to exclude from consideration
+exclude_lines =
+    # Have to re-enable the standard pragma
+    pragma: no cover
+
+    # Don't complain if tests don't hit defensive assertion code:
+    raise NotImplementedError
+    pass

.gitignore

@@ -9,8 +9,9 @@ build/
 dist/
 MANIFEST
 .tox
-.coveragerc
+.coverage
 # WebDAV file system cache files
 .DAV/
 _test/
 .vscode
+htmlcov/

.travis.yml

@@ -10,20 +10,24 @@ branches:
     - master
 
 python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
   - "3.6"
   - "3.7"
+  - "3.8"
 
 install:
-  - if [ $TRAVIS_PYTHON_VERSION == '2.7' ] || [ $TRAVIS_PYTHON_VERSION == '3.6' ]; then pip install numpy; fi
-  - pip install coverage coveralls
+  - if [ $TRAVIS_PYTHON_VERSION == '3.6' ]; then pip install numpy; fi
+  - pip install pytest pytest-cov
+
+  # Install codecov report tools
+  - pip install codecov
+
+before_install:
+  - cd $TRAVIS_BUILD_DIR
+  - python setup.py develop
 
 script:
-  - coverage run -p --source=pyvisa --omit="*test*","*compat*" setup.py test
-  - coverage combine
-  - coverage report -m
+  - pytest pyvisa -v --cov pyvisa
 
-after_script:
-  - coveralls --verbose
+after_success:
+  - cd $TRAVIS_BUILD_DIR
+  - codecov

CHANGES

@@ -4,6 +4,20 @@ PyVISA Changelog
 1.11 (unreleased)
 -----------------
 
+- Drop Python 2 support PR #486
+- Limit support to Python 3.6+ PR #486
+- Improve the test suite and introduce tests relying on Keysight Virtual
+  instrument software PR #486
+- Add badges to the README PR #486
+- Improve ResourceManager.list_opened_resource to list only open resources.
+  Previously all resources created and not yet garbage collected were listed. PR #486
+- Always normalize resource names PR #486
+- Treat floating points number as double when parsing ASCII data blocks PR #486
+- Allow bound methods as handler function (the use of is in tests prevented it) PR #486
+- Deprecate some unused functions found in the util.py module PR #486
+- Warn or raise if the beginning of a binary block is not found among the first characters.
+  The default value is 25. PR #486
+-
 - Make the library less biased towards National Instrument by referring to IVI
   where relevant. In particular rename the @ni backend to @ivi PR #456
 - Deprecate the `visa` module that is causing issue with the VISA payment

README.rst

@@ -1,11 +1,27 @@
 PyVISA
 ======
 
+
+.. image:: https://travis-ci.org/pyvisa/pyvisa.svg?branch=master
+    :target: https://travis-ci.org/pyvisa/pyvisa
+    :alt: Build Status
+.. image:: https://codecov.io/gh/pyvisa/pyvisa/branch/master/graph/badge.svg
+    :target: https://codecov.io/gh/pyvisa/pyvisa
+    :alt: Code Coverage
+.. image:: https://readthedocs.org/projects/pyvisa/badge/?version=latest
+    :target: https://pyvisa.readthedocs.io/en/latest/?badge=latest
+    :alt: Documentation Status
+.. image:: https://img.shields.io/pypi/l/PyVISA
+    :target: https://pypi.python.org/pypi/pyvisa
+    :alt: PyPI - License
+.. image:: https://img.shields.io/pypi/v/PyVISA
+    :target: https://pypi.python.org/pypi/pyvisa
+    :alt: PyPI
+
 A Python package for support of the "Virtual Instrument Software
 Architecture" (VISA), in order to control measurement devices and
 test equipment via GPIB, RS232, Ethernet or USB.
 
-
 Description
 -----------
 

docs/source/introduction/resources.rst

@@ -29,8 +29,8 @@ The following sections explore the most common attributes of ``Resource`` and
 often. For more information, refer to the :ref:`api`.
 
 
-Attributes Resource
--------------------
+Attributes of Resource
+----------------------
 
 session
 ~~~~~~~

pyvisa/__init__.py

@@ -10,15 +10,11 @@
     :copyright: 2014-2019 by PyVISA Authors, see AUTHORS for more details.
     :license: MIT, see LICENSE for more details.
 """
-
-from __future__ import division, unicode_literals, print_function, absolute_import
-
 import logging
 import pkg_resources
 
-from . import compat
 logger = logging.getLogger('pyvisa')
-logger.addHandler(compat.NullHandler())
+logger.addHandler(logging.NullHandler())
 
 
 def log_to_screen(level=logging.DEBUG):

pyvisa/attributes.py

@@ -10,12 +10,8 @@
     :copyright: 2014 by PyVISA Authors, see AUTHORS for more details.
     :license: MIT, see LICENSE for more details.
 """
-
-from __future__ import division, unicode_literals, print_function, absolute_import
-
 from collections import defaultdict
 
-from .compat import with_metaclass
 from . import constants
 
 #: Not available value.
@@ -53,8 +49,9 @@ def __init__(cls, name, bases, dct):
         AttributesByID[cls.attribute_id] = cls
 
 
-class Attribute(with_metaclass(AttributeType)):
+class Attribute(object, metaclass=AttributeType):
     """Base class for Attributes to be used as Properties.
+
     """
 
     #: List of resource types with this attribute.
@@ -143,11 +140,18 @@ def post_get(self, value):
         return self.enum_type(value)
 
     def pre_set(self, value):
-        if value not in self.enum_type:
+        # Python 3.8 raise if a non-Enum is used for value
+        try:
+            if value not in self.enum_type:
+                raise ValueError('%r is an invalid value for attribute %s, '
+                                'should be a %r' % (value,
+                                                    self.visa_name,
+                                                    self.enum_type))
+        except TypeError:
             raise ValueError('%r is an invalid value for attribute %s, '
-                             'should be a %r' % (value,
-                                                 self.visa_name,
-                                                 self.enum_type))
+                                'should be a %r' % (value,
+                                                    self.visa_name,
+                                                    self.enum_type))
         return value
 
 
@@ -608,7 +612,7 @@ class AttrVI_ATTR_ASRL_PARITY(EnumAttribute):
 
 
 # noinspection PyPep8Naming
-class AttrVI_ATTR_ASRL_REPLACE_CHAR(RangeAttribute):
+class AttrVI_ATTR_ASRL_REPLACE_CHAR(CharAttribute):
     """VI_ATTR_ASRL_REPLACE_CHAR specifies the character to be used to
     replace incoming characters that arrive with errors (such as
     parity error).
@@ -625,8 +629,6 @@ class AttrVI_ATTR_ASRL_REPLACE_CHAR(RangeAttribute):
 
     read, write, local = True, True, True
 
-    min_value, max_value, values = 0, 0xFF, []
-
 
 # noinspection PyPep8Naming
 class AttrVI_ATTR_ASRL_RI_STATE(EnumAttribute):
@@ -714,7 +716,7 @@ class AttrVI_ATTR_ASRL_WIRE_MODE(RangeAttribute):
 
 
 # noinspection PyPep8Naming
-class AttrVI_ATTR_ASRL_XOFF_CHAR(RangeAttribute):
+class AttrVI_ATTR_ASRL_XOFF_CHAR(CharAttribute):
     """VI_ATTR_ASRL_XOFF_CHAR specifies the value of the XOFF character used
     for XON/XOFF flow control (both directions). If XON/XOFF flow
     control (software handshaking) is not being used, the value of
@@ -732,11 +734,9 @@ class AttrVI_ATTR_ASRL_XOFF_CHAR(RangeAttribute):
 
     read, write, local = True, True, True
 
-    min_value, max_value, values = 0, 0xFF, []
-
 
 # noinspection PyPep8Naming
-class AttrVI_ATTR_ASRL_XON_CHAR(RangeAttribute):
+class AttrVI_ATTR_ASRL_XON_CHAR(CharAttribute):
     """VI_ATTR_ASRL_XON_CHAR specifies the value of the XON character used
     for XON/XOFF flow control (both directions). If XON/XOFF flow
     control (software handshaking) is not being used, the value of
@@ -754,8 +754,6 @@ class AttrVI_ATTR_ASRL_XON_CHAR(RangeAttribute):
 
     read, write, local = True, True, True
 
-    min_value, max_value, values = 0, 0xFF, []
-
 
 # Could not generate class for VI_ATTR_BUFFER.html
 # Exception:
@@ -860,7 +858,7 @@ class AttrVI_ATTR_DEST_INCREMENT(RangeAttribute):
 
 
 # noinspection PyPep8Naming
-class AttrVI_ATTR_DEV_STATUS_BYTE(RangeAttribute):
+class AttrVI_ATTR_DEV_STATUS_BYTE(CharAttribute):
     """This attribute specifies the 488-style status byte of the local
     controller or device associated with this session.
     """
@@ -877,8 +875,6 @@ class AttrVI_ATTR_DEV_STATUS_BYTE(RangeAttribute):
 
     read, write, local = True, True, False
 
-    min_value, max_value, values = 0, 0xFF, []
-
 
 # noinspection PyPep8Naming
 class AttrVI_ATTR_DMA_ALLOW_EN(BooleanAttribute):
@@ -2480,7 +2476,7 @@ class AttrVI_ATTR_TCPIP_PORT(RangeAttribute):
 
 
 # noinspection PyPep8Naming
-class AttrVI_ATTR_TERMCHAR(RangeAttribute):
+class AttrVI_ATTR_TERMCHAR(CharAttribute):
     """VI_ATTR_TERMCHAR is the termination character. When the termination
     character is read and VI_ATTR_TERMCHAR_EN is enabled during a read
     operation, the read operation terminates.
@@ -2505,8 +2501,6 @@ class AttrVI_ATTR_TERMCHAR(RangeAttribute):
 
     read, write, local = True, True, True
 
-    min_value, max_value, values = 0, 0xFF, []
-
 
 # noinspection PyPep8Naming
 class AttrVI_ATTR_TERMCHAR_EN(BooleanAttribute):