Clean up coverage writing

.coveragerc

@@ -0,0 +1,17 @@
+[run]
+data_file = coverage/.coverage
+branch = true
+
+[paths]
+source = fairtally/
+
+[html]
+directory = coverage/htmlcov/
+
+[xml]
+output = coverage/coverage.xml
+
+[report]
+omit =
+    venv*
+    tests/*

coverage/README.md

@@ -0,0 +1,31 @@
+# Coverage reporting
+
+The coverage reports will be written in this directory. After running `pytest`, the directory should look more or less like this:
+
+```text
+coverage/
+├── .coverage
+├── coverage.xml
+├── htmlcov
+│   ├── coverage_html.js
+│   ├── fairtally_check_py.html
+│   ├── fairtally_cli_py.html
+│   ├── fairtally___init___py.html
+│   ├── fairtally_redirect_stdout_stderr_py.html
+│   ├── fairtally_utils_py.html
+│   ├── fairtally___version___py.html
+│   ├── favicon_32.png
+│   ├── index.html
+│   ├── jquery.ba-throttle-debounce.min.js
+│   ├── jquery.hotkeys.js
+│   ├── jquery.isonscreen.js
+│   ├── jquery.min.js
+│   ├── jquery.tablesorter.min.js
+│   ├── keybd_closed.png
+│   ├── keybd_open.png
+│   ├── status.json
+│   └── style.css
+└── README.md
+```
+
+Everything except the README is generated (see configuration in `/.coveragerc`).

setup.cfg

@@ -22,16 +22,12 @@ build-dir = docs/_build
 all_files = 1
 builder = html
 
-[coverage:run]
-branch = True
-source = fairtally
-
 [metadata]
 description-file = README.rst
 
 [tool:pytest]
 testpaths = tests
-addopts = --cov --cov-report xml --cov-report term --cov-report html
+addopts = --cov --cov-config=.coveragerc --cov-report html --cov-report term --cov-report xml
 
 [tool:isort]
 lines_after_imports = 2