diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 59e6e3763..cb2f31864 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -15,6 +15,7 @@ repos:
     rev: v1.0.1
     hooks:
     -   id: seed-isort-config
+        args: [--application-directories, src]
 -   repo: https://github.com/pre-commit/mirrors-isort
     rev: v4.3.4
     hooks:
diff --git a/setup.py b/setup.py
index ea47156b5..9a30a85ac 100644
--- a/setup.py
+++ b/setup.py
@@ -43,7 +43,8 @@ def main():
         platforms=["unix", "linux", "osx", "cygwin", "win32"],
         author="holger krekel",
         author_email="holger@merlinux.eu",
-        packages=["tox"],
+        packages=setuptools.find_packages("src"),
+        package_dir={"": "src"},
         entry_points={
             "console_scripts": ["tox=tox:cmdline", "tox-quickstart=tox._quickstart:main"]
         },
@@ -59,7 +60,6 @@ def main():
                 "pytest-xdist",
             ],
             "docs": ["sphinx >= 1.6.3, < 2", "towncrier >= 17.8.0"],
-            "lint": ["pre-commit == 1.8.2"],
             "publish": ["devpi", "twine"],
         },
         classifiers=[
diff --git a/tox/__init__.py b/src/tox/__init__.py
similarity index 100%
rename from tox/__init__.py
rename to src/tox/__init__.py
diff --git a/tox/__main__.py b/src/tox/__main__.py
similarity index 100%
rename from tox/__main__.py
rename to src/tox/__main__.py
diff --git a/tox/_pytestplugin.py b/src/tox/_pytestplugin.py
similarity index 100%
rename from tox/_pytestplugin.py
rename to src/tox/_pytestplugin.py
diff --git a/tox/_quickstart.py b/src/tox/_quickstart.py
similarity index 100%
rename from tox/_quickstart.py
rename to src/tox/_quickstart.py
diff --git a/tox/_verlib.py b/src/tox/_verlib.py
similarity index 100%
rename from tox/_verlib.py
rename to src/tox/_verlib.py
diff --git a/tox/config.py b/src/tox/config.py
similarity index 100%
rename from tox/config.py
rename to src/tox/config.py
diff --git a/tox/constants.py b/src/tox/constants.py
similarity index 100%
rename from tox/constants.py
rename to src/tox/constants.py
diff --git a/tox/exception.py b/src/tox/exception.py
similarity index 100%
rename from tox/exception.py
rename to src/tox/exception.py
diff --git a/tox/hookspecs.py b/src/tox/hookspecs.py
similarity index 100%
rename from tox/hookspecs.py
rename to src/tox/hookspecs.py
diff --git a/tox/interpreters.py b/src/tox/interpreters.py
similarity index 100%
rename from tox/interpreters.py
rename to src/tox/interpreters.py
diff --git a/tox/result.py b/src/tox/result.py
similarity index 100%
rename from tox/result.py
rename to src/tox/result.py
diff --git a/tox/session.py b/src/tox/session.py
similarity index 100%
rename from tox/session.py
rename to src/tox/session.py
diff --git a/tox/venv.py b/src/tox/venv.py
similarity index 100%
rename from tox/venv.py
rename to src/tox/venv.py
diff --git a/tox.ini b/tox.ini
index 46a892b81..35807d428 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,20 +12,25 @@ skip_missing_interpreters = true
 
 [testenv]
 description = run the tests with pytest under {basepython}
-setenv = COVERAGE_FILE={toxworkdir}/.coverage.{envname}
+setenv = PIP_DISABLE_VERSION_CHECK = 1
+         COVERAGE_FILE = {toxworkdir}/.coverage.{envname}
 passenv = http_proxy https_proxy no_proxy SSL_CERT_FILE TOXENV CI TRAVIS TRAVIS_* APPVEYOR APPVEYOR_* CODECOV_*
+deps =
 extras = testing
-commands = pytest {posargs:--cov-config="{toxinidir}/tox.ini" --cov="{envsitepackagesdir}/tox" --timeout=180 tests}
+changedir = {toxinidir}/tests
+commands = pytest {posargs:--cov="{envsitepackagesdir}/tox" --cov-config="{toxinidir}/tox.ini"  --timeout=180 .}
 
 [testenv:docs]
 description = invoke sphinx-build to build the HTML docs and check that all links are valid
 whitelist_externals = sphinx-build
 basepython = python3.6
 extras = docs
+changedir = {toxinidir}
 commands = sphinx-build -d "{toxworkdir}/docs_doctree" doc "{toxworkdir}/docs_out" --color -W -bhtml
 
 
 [testenv:fix-lint]
+description = format the code base to adhere to our styles, and complain about what we cannot do automatically
 basepython = python3.6
 passenv = {[testenv]passenv}
           HOMEPATH
@@ -33,26 +38,35 @@ passenv = {[testenv]passenv}
           # `error setting certificate verify locations` error
           PROGRAMDATA
 extras = lint
-description = run static analysis and style check using flake8
+deps = pre-commit == 1.10.1
+skip_install = True
+changedir = {toxinidir}
 commands = pre-commit run --all-files --show-diff-on-failure
            python -c 'print("hint: run {envdir}/bin/pre-commit install to add checks as pre-commit hook")'
 
 
 [testenv:coverage]
-description = combine coverage data and create reports
-deps = coverage
+description = [run locally after tests]: combine coverage data and create report;
+              generates a diff coverage against origin/master (can be changed by setting DIFF_AGAINST env var)
+deps = {[testenv]deps}
+       coverage >= 4.4.1, < 5
+       diff_cover
 skip_install = True
-changedir = {toxworkdir}
-setenv = COVERAGE_FILE=.coverage
+passenv = {[testenv]passenv}
+          DIFF_AGAINST
+setenv = COVERAGE_FILE={toxworkdir}/.coverage
+changedir = {toxinidir}
 commands = coverage erase
            coverage combine
-           coverage report --rcfile="{toxinidir}/tox.ini"
-           coverage xml
+           coverage report -m
+           coverage xml -o {toxworkdir}/coverage.xml
+           diff-cover --compare-branch {env:DIFF_AGAINST:origin/master} {toxworkdir}/coverage.xml
 
 [testenv:codecov]
 description = [only run on CI]: upload coverage data to codecov (depends on coverage running first)
 deps = codecov
 skip_install = True
+changedir = {toxinidir}
 commands = codecov --file "{toxworkdir}/coverage.xml"
 
 [testenv:exit_code]
@@ -61,6 +75,7 @@ commands = codecov --file "{toxworkdir}/coverage.xml"
 basepython = python3.6
 description = commands with several exit codes
 skip_install = True
+changedir = {toxinidir}
 commands = python3.6 -c "import sys; sys.exit(139)"
 
 [testenv:pra]
@@ -68,6 +83,7 @@ platform = linux
 passenv = *
 description = "personal release assistant" - see HOWTORELEASE.rst
 extras = publish, docs
+changedir = {toxinidir}
 commands = sphinx-build -d "{toxworkdir}/docs_doctree" doc "{toxworkdir}/docs_out" --color -W -blinkcheck
            "{toxinidir}/tasks/pra.sh" {posargs}
 
@@ -81,6 +97,7 @@ extras = testing, docs
 # required to make looponfail reload on every source code change
 usedevelop = True
 basepython = python3.6
+changedir = {toxinidir}
 commands = python -m pip list --format=columns
            python -c 'import sys; print(sys.executable)'
 
@@ -90,7 +107,7 @@ max-line-length = 99
 ignore = E203, W503
 
 [coverage:run]
-omit = tox/__main__.py
+branch = true
 
 [coverage:report]
 skip_covered = True
@@ -98,13 +115,13 @@ show_missing = True
 exclude_lines = if __name__ == ["']__main__["']:
 
 [coverage:paths]
-source = tox
-         {toxworkdir}/*/lib/python*/site-packages/tox
-         {toxworkdir}/*/Lib/site-packages/tox
-         {toxworkdir}/pypy*/site-packages/tox
+source = src/tox
+         .tox/*/lib/python*/site-packages/tox
+         .tox/*/Lib/site-packages/tox
+         .tox/pypy*/site-packages/tox
 
 [pytest]
-addopts = -rsxX -vvv --showlocals
+addopts = -rsxX --showlocals
 rsyncdirs = tests tox
 looponfailroots = tox tests
 norecursedirs = .hg .tox