diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..54c66a0
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,9 @@
+[run]
+source = zope.size
+
+[report]
+exclude_lines =
+    pragma: no cover
+    if __name__ == '__main__':
+    raise NotImplementedError
+    self.fail
diff --git a/.gitignore b/.gitignore
index 6471d6c..605e07a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,5 +10,6 @@ bin
 build
 develop-eggs
 parts
-
+.coverage
+htmlcov/
 docs/_build/
diff --git a/.travis.yml b/.travis.yml
index 2428b54..26ae120 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,14 +2,19 @@ language: python
 sudo: false
 python:
     - 2.7
-    - 3.3
     - 3.4
     - 3.5
+    - 3.6
     - pypy
-    - pypy3
+    - pypy3.5-5.8.0
 install:
-    - pip install .
+    - pip install -U pip setuptools
+    - pip install -U coverage coveralls
+    - pip install -U -e .[test]
 script:
-    - python setup.py test -q
+    - coverage run setup.py -q test -q
+after_success:
+    - coveralls
 notifications:
     email: false
+cache: pip
diff --git a/CHANGES.rst b/CHANGES.rst
index 29e3a90..0ad2b4f 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,9 +4,9 @@ Changes
 4.2.0 (unreleased)
 ------------------
 
-- Add support for Python 3.5.
+- Add support for Python 3.5 and 3.6.
 
-- Drop support for Python 2.6 and 3.2.
+- Drop support for Python 2.6, 3.2 and 3.3.
 
 
 4.1.0 (2014-12-29)
@@ -35,7 +35,7 @@ Changes
 
 - Add support for Python 3.2 and 3.3.
 
-- Conditionally disable tests that require ``zope.configuration`` and 
+- Conditionally disable tests that require ``zope.configuration`` and
   ``zope.security``.
 
 
diff --git a/MANIFEST.in b/MANIFEST.in
index 1c92fd0..130ef25 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,2 +1,15 @@
-include *.txt bootstrap.py buildout.cfg tox.ini
-recursive-include src *.py *.txt *.zcml
+include *.txt
+include *.rst
+include bootstrap.py
+include buildout.cfg
+include tox.ini
+include .travis.yml
+include .coveragerc
+
+recursive-include src *.py
+recursive-include src *.txt
+recursive-include src *.zcml
+
+recursive-include docs *.py
+recursive-include docs *.rst
+recursive-include docs Makefile
diff --git a/README.rst b/README.rst
index 64c2231..602447d 100644
--- a/README.rst
+++ b/README.rst
@@ -1,13 +1,25 @@
-``zope.size``
-=============
+===============
+ ``zope.size``
+===============
+
+.. image:: https://img.shields.io/pypi/v/zope.size.svg
+        :target: https://pypi.python.org/pypi/zope.size/
+        :alt: Latest release
+
+.. image:: https://img.shields.io/pypi/pyversions/zope.size.svg
+        :target: https://pypi.org/project/zope.size/
+        :alt: Supported Python versions
 
 .. image:: https://travis-ci.org/zopefoundation/zope.size.png?branch=master
         :target: https://travis-ci.org/zopefoundation/zope.size
 
 .. image:: https://readthedocs.org/projects/zopesize/badge/?version=latest
-        :target: http://zopesize.readthedocs.io/en/latest/?badge=latest
+        :target: https://zopesize.readthedocs.io/en/latest/
         :alt: Documentation Status
 
+.. image:: https://coveralls.io/repos/github/zopefoundation/zope.size/badge.svg?branch=master
+        :target: https://coveralls.io/github/zopefoundation/zope.size?branch=master
+
 This package provides a definition of simple interface that allows
 applications to retrieve the size of the object for displaying and for sorting.
 
@@ -16,3 +28,5 @@ method that returns size in bytes.  However, the adapter won't crash if an
 object doesn't have one and will show size as "not available" instead.
 
 Development is hosted at https://github.com/zopefoundation/zope.size
+
+Documentation is hosted at https://zopesize.readthedocs.io
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..2a9acf1
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1
diff --git a/setup.py b/setup.py
index 728ad89..651fa31 100644
--- a/setup.py
+++ b/setup.py
@@ -25,47 +25,56 @@ def read(*rnames):
     with open(os.path.join(os.path.dirname(__file__), *rnames)) as f:
         return f.read()
 
+ZCML_REQUIRES = [
+    'zope.component[zcml]',
+    'zope.configuration',
+    'zope.security[zcml]',
+]
+
+TESTS_REQUIRE = ZCML_REQUIRES
+
 setup(name='zope.size',
-      version=read('version.txt'),
-      url='http://zopesize.readthedocs.io',
+      version=read('version.txt').strip(),
+      url='http://github.com/zopefoundation/zope.size',
       license='ZPL 2.1',
       description=\
           'Interfaces and simple adapter that give the size of an object',
+      keywords="size display human bytes",
       author='Zope Foundation and Contributors',
       author_email='zope-dev@zope.org',
       long_description=read('README.rst') + '\n\n' + read('CHANGES.rst'),
       classifiers=[
-        'Development Status :: 5 - Production/Stable',
-        'Intended Audience :: Developers',
-        'License :: OSI Approved :: Zope Public License',
-        'Programming Language :: Python',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.3',
-        'Programming Language :: Python :: 3.4',
-        'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: Implementation :: CPython',
-        'Programming Language :: Python :: Implementation :: PyPy',
-        'Natural Language :: English',
-        'Operating System :: OS Independent',
-        'Topic :: Internet :: WWW/HTTP',
-        'Topic :: Software Development',
-        ],
+          'Development Status :: 5 - Production/Stable',
+          'Intended Audience :: Developers',
+          'License :: OSI Approved :: Zope Public License',
+          'Programming Language :: Python',
+          'Programming Language :: Python :: 2',
+          'Programming Language :: Python :: 2.7',
+          'Programming Language :: Python :: 3',
+          'Programming Language :: Python :: 3.4',
+          'Programming Language :: Python :: 3.5',
+          'Programming Language :: Python :: 3.6',
+          'Programming Language :: Python :: Implementation :: CPython',
+          'Programming Language :: Python :: Implementation :: PyPy',
+          'Natural Language :: English',
+          'Operating System :: OS Independent',
+          'Topic :: Internet :: WWW/HTTP',
+          'Topic :: Software Development',
+      ],
       packages=find_packages('src'),
-      package_dir = {'': 'src'},
+      package_dir={'': 'src'},
       namespace_packages=['zope'],
-      tests_require = [],
+      tests_require=TESTS_REQUIRE,
       test_suite='zope.size.tests.test_suite',
-      extras_require=dict(
-          zcml=[
-            'zope.component[zcml]',
-            'zope.configuration',
-            'zope.security[zcml]',
-            ]),
-      install_requires=['setuptools',
-                        'zope.interface',
-                        'zope.i18nmessageid'],
-      include_package_data = True,
-      zip_safe = False,
-      )
+      extras_require={
+          'zcml': ZCML_REQUIRES,
+          'test': TESTS_REQUIRE,
+      },
+      install_requires=[
+          'setuptools',
+          'zope.interface',
+          'zope.i18nmessageid',
+      ],
+      include_package_data=True,
+      zip_safe=False,
+)
diff --git a/src/zope/__init__.py b/src/zope/__init__.py
index de40ea7..2cdb0e4 100644
--- a/src/zope/__init__.py
+++ b/src/zope/__init__.py
@@ -1 +1 @@
-__import__('pkg_resources').declare_namespace(__name__)
+__import__('pkg_resources').declare_namespace(__name__) # pragma: no cover
diff --git a/src/zope/size/tests.py b/src/zope/size/tests.py
index 3456050..01267f0 100644
--- a/src/zope/size/tests.py
+++ b/src/zope/size/tests.py
@@ -18,11 +18,8 @@
 from zope.size.interfaces import ISized
 import zope.size
 
-try:
-    import zope.component
-    import zope.configuration.xmlconfig
-except:
-    pass
+import zope.component
+import zope.configuration.xmlconfig
 
 
 class ZCMLTest(unittest.TestCase):
@@ -31,7 +28,7 @@ def test_configure_zcml_should_be_loadable(self):
         try:
             zope.configuration.xmlconfig.XMLConfig(
                 'configure.zcml', zope.size)()
-        except Exception as e:
+        except Exception as e: # pragma: no cover
             self.fail(e)
 
     def test_configure_should_register_n_components(self):
@@ -117,11 +114,4 @@ def test_byteDisplay(self):
 
 
 def test_suite():
-    tests = [Test]
-    try:
-        import zope.configuration
-        tests.append(ZCMLTest)
-    except:
-        pass
-
-    return unittest.TestSuite([unittest.makeSuite(cls) for cls in tests])
+    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/tox.ini b/tox.ini
index 37e3d08..1e5cacd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,19 @@
 [tox]
-envlist = py27,py33,py34,py35,pypy,pypy3
+envlist = py27,py34,py35,py36,pypy,pypy3
 
 [testenv]
-commands = python setup.py -q test -q
-deps = zope.testrunner
+commands =
+    python setup.py -q test -q
+deps =
+    .[test]
+
+[testenv:coverage]
+usedevelop = true
+basepython =
+    python2.7
+commands =
+    coverage run setup.py -q test -q
+    coverage report --fail-under=100
+deps =
+    {[testenv]deps}
+    coverage