Cleanup tox configuration

There were issues with dependencies and tox environments under Python 3
so refactored the tox configuration to be more consistent and clearer.

- Moved travis to default to Python 3 for linting and tests.
- Fixed missing mock for cairo in sphinx config.
- Collated the base deps sections to improve readability.
- Added PYTEST_ADDOPTS env to override pytest verbosity in just tox
  tests as this was a common option being used.
- Renamed env 'testcoverage' to the more concise 'coverage' and moved
  html creation under single env as handy to have this output as well
  as report.
- Cleaned up the isort config for gtk3.
- Added `bad-continuation` to pylint config as conflcts with black
  formatting.
- Fix isort issue with bbfreeze script. This will likely be removed
  in future so just skip sorting it.

1 files changed, 78 insertions, 88 deletions

diff --git a/tox.ini b/tox.ini
index 134cde2a6..cb24c5547 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,31 +5,60 @@
 
 [tox]
 envlist = py27, py3, lint, docs
-minversion=2.0
+minversion=3.0
 
-[base]
+[pytest]
+# Hide logged warnings and errors in test output.
+log_cli_level = CRITICAL
+addopts = -p no:warnings --basetemp=_pytest_temp
+
+# =================
+# Base dependencies
+# =================
+[basesetup]
+# Minimum pip and setuptools versions to fix system and travis issues.
 deps =
-# Minimum pip version and setuptools to fix issue running on travis.
     pip>=10
-    setuptools
+    setuptools>=40
+
+[basetests]
+deps =
+    {[basesetup]deps}
+    -rrequirements.txt
+    -rrequirements-tests.txt
+
+[baselint]
+deps =
+    {[basesetup]deps}
+    -rrequirements-tests.txt
+
+[basedev]
+deps =
+    {[basesetup]deps}
     -rrequirements.txt
+    -rrequirements-dev.txt
+    -rrequirements-tests.txt
+
+[basedocs]
+deps =
+    {[basesetup]deps}
+    -rrequirements-docs.txt
+
+# ======================
+# Test environment setup
+# ======================
 
 [testenv]
-install_command = {envpython} -m pip install --ignore-installed {opts} {packages}
+install_command = python -m pip install --ignore-installed {opts} {packages}
 passenv = DISPLAY PYTHONPATH
-setenv = PYTHONPATH = {toxinidir}
+setenv =
+    PYTHONPATH = {toxinidir}
+    PYTEST_ADDOPTS = -v -s
 sitepackages = True
-deps =
-    {[base]deps}
-    -rrequirements-tests.txt
+deps = {[basetests]deps}
 commands =
     python -c "import libtorrent as lt; print(lt.__version__)"
-    pytest -v -s -m "not (todo or gtkui or security)" deluge/tests
-
-[pytest]
-# Hide logged warnings and errors in test output.
-log_cli_level = CRITICAL
-addopts = -p no:warnings --basetemp=_pytest_temp
+    pytest -m "not (todo or gtkui or security)" deluge/tests
 
 # ==========
 # Unit tests
@@ -37,13 +66,13 @@ addopts = -p no:warnings --basetemp=_pytest_temp
 
 [testenv:security]
 setenv = SECURITY_TESTS = True
-commands = pytest -v -s -m "security" deluge/tests/
+commands = pytest -m "security" deluge/tests
 
-[testenv:pygtkui]
-commands = pytest -v -s -m "gtkui" deluge/tests
+[testenv:gtkui]
+commands = pytest -m "gtkui" deluge/tests
 
 [testenv:todo]
-commands = pytest -v -s -m "todo" deluge/tests
+commands = pytest -m "todo" deluge/tests
 
 [testenv:trial]
 setenv = {[testenv]setenv}{:}{toxinidir}/deluge/tests
@@ -55,56 +84,44 @@ commands =
 setenv = PYTHONPATH = {toxinidir}{:}{toxinidir}/deluge/plugins
 commands =
     python setup.py build_plugins --develop --install-dir={toxinidir}/deluge/plugins/
-    pytest -v -s -m "not gtkui" deluge/plugins
+    pytest -m "not gtkui" deluge/plugins
 
 [testenv:pluginsgtkui]
 setenv = PYTHONPATH = {toxinidir}{:}{toxinidir}/deluge/plugins
 commands =
     python setup.py build_plugins --develop --install-dir={toxinidir}/deluge/plugins/
-    pytest -v -s deluge/plugins
+    pytest deluge/plugins
 
-
-# =======================
+# ============
 # Code linting
-# =======================
+# ============
+
+# Disable site-packages to avoid using system installed commands.
 
 [testenv:lint]
+sitepackages = False
 passenv = HOMEPATH SSH_AUTH_SOCK
-deps =
-    pre-commit
-commands =
-    pre-commit run --all-files
+deps = {[baselint]deps}
+commands = pre-commit run --all-files
 
 [testenv:flake8]
-# Disable site packages to avoid using system flake8 which uses
-# hardcoded python path which imports the wrong libraries.
 sitepackages = False
-deps =
-    {[testenv]deps}
-    flake8
-    flake8-quotes
-    flake8-isort
-    pep8-naming
+deps = {[baselint]deps}
 commands =
     flake8 --version
     python -c 'import isort; print(isort.__version__)'
-    flake8
+    flake8 *.py deluge
 
 [testenv:flake8-complexity]
 sitepackages = False
-deps =
-    {[testenv:flake8]deps}
-    mccabe
+deps = {[baselint]deps}
 commands = flake8 --exit-zero --max-complexity 15 deluge
 
-
 [testenv:pylint]
-# Disable site packages to avoid using system installed version
+
 sitepackages = False
 ignore_errors = True
-deps =
-    {[testenv]deps}
-    pylint
+deps = {[baselint]deps}
 commands =
     pylint --version
     pylint deluge
@@ -112,63 +129,40 @@ commands =
     python -m pylint *.py deluge/scripts/*.py
     python -m pylint deluge/plugins/*/deluge/
 
+# ========
+# Coverage
+# ========
 
-# =============
-# Test coverage
-# =============
+[coveragebase]
+commands = coverage run --branch --source=deluge -m pytest -m "not todo" deluge/tests
 
-[testcoveragebase]
-deps =
-    {[testenv]deps}
-    pytest-cov
-    coverage
-commands = coverage run --branch --source=deluge -m pytest -m "not todo" deluge/tests/
-
-[testenv:testcoverage]
-setenv = {[testenv]setenv}
-deps = {[testcoveragebase]deps}
+[testenv:coverage]
 commands =
-    {[testcoveragebase]commands}
-    coverage report
-
-[testenv:testcoverage-html]
-setenv = {[testenv]setenv}
-deps = {[testcoveragebase]deps}
-commands =
-    {[testcoveragebase]commands}
+    {[coveragebase]commands}
     coverage html -d docs/build/htmlcoverage
-
+    coverage report
 
 # ===================
 # Documentation build
 # ===================
 
-# We do not have all dependencies on RTD and travis so we exclude the
-# site packages (sitepackages=False) when building docs so that local
-# tests have a similar environment.
-
-[docsbase]
-sitepackages = False
-changedir = docs
-deps =
-    -rrequirements-docs.txt
-
 [testenv:docs]
 basepython = python2.7
-sitepackages = {[docsbase]sitepackages}
+# Exclude site-packages so local builds have a similar environment to ReadTheDocs.
+sitepackages = False
 skip_install = True
-deps = {[docsbase]deps}
+deps = {[basedocs]deps}
 commands =
     python setup.py clean_docs
     sphinx-build -v -j auto -E -T -b html -d docs/build/doctrees docs/source docs/build/html
 
 [testenv:docscoverage]
 basepython = python2.7
-sitepackages = {[docsbase]sitepackages}
+sitepackages = False
 skip_install = True
-changedir = {[docsbase]changedir}
+changedir = docs
 deps =
-    {[docsbase]deps}
+    {[basedocs]deps}
     pytest-cov
 whitelist_externals = mkdir
 commands =
@@ -176,24 +170,20 @@ commands =
     sphinx-build -W -b coverage -d build/doctrees source build/doccoverage
     pytest --doctest-glob='*.rst'
 
-
 # ========================
 # Development Environment
 # ========================
-[basedev]
-usedevelop = True
-deps = -rrequirements-dev.txt
 
 [testenv:denv2]
 basepython = python2.7
 envdir = .venv2
-usedevelop = {[basedev]usedevelop}
+usedevelop = True
 deps = {[basedev]deps}
 commands =
 
 [testenv:denv3]
 basepython = python3
 envdir = .venv3
-usedevelop = {[basedev]usedevelop}
+usedevelop = True
 deps = {[basedev]deps}
 commands =