fix: dev: tox, coverage, lint

Makefile

@@ -88,7 +88,9 @@ test:
 	tox -e default -- $(_PYTEST_OPTS) $(_PDB_OPTS)
 
 test-all:
+	tox -e clean
 	tox --parallel=all
+	tox -e coverage
 
 test-data:
 	# Move these to eyed3.nicfit.net
@@ -106,10 +108,13 @@ pkg-test-data:
 	 tar czf ./build/${TEST_DATA_FILE} -C ./test ./eyeD3-test-data
 
 coverage:
-	tox -e default,coverage
+	tox -e coverage
 
-coverage-view: coverage
-	${BROWSER} build/tests/coverage/index.html;\
+coverage-view:
+	@if [ ! -f build/tests/coverage/index.html ]; then \
+		${MAKE} coverage; \
+	fi
+	@${BROWSER} build/tests/coverage/index.html
 
 docs:
 	rm -f docs/eyed3.rst

eyed3/mp3/headers.py

@@ -365,7 +365,7 @@ def decode(self, frame):
 
 
 class LameHeader(dict):
-    """ Mp3 Info tag (AKA LAME Tag)
+    r""" Mp3 Info tag (AKA LAME Tag)
 
     Lame (and some other encoders) write a tag containing various bits of info
     about the options used at encode time.  If available, the following are

tox.ini

@@ -1,33 +1,35 @@
 [tox]
-envlist = clean, py{36,37,38}, coverage, lint
+envlist = py{36,37,38}
+
+[default]
+python = python3.7
 
 [testenv:default]
-basepython = python3.7
-             lint: python3.7
-             coverage: python3.7
+basepython = {[default]python}
 
 [testenv:clean]
 skipsdist = true
 skip_install = true
 commands = coverage erase
 
 [testenv]
-commands = coverage run --rcfile=setup.cfg --source ./eyed3 --append -m \
-           pytest {posargs:--verbose ./test}
+commands = pytest {posargs:--verbose ./test}
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/requirements/test.txt
 
 [testenv:coverage]
+basepython = {[default]python}
 commands =
+    coverage run --rcfile=setup.cfg --source ./eyed3 -m \
+             pytest {posargs:--verbose ./test}
     coverage report --rcfile=setup.cfg
     coverage html --rcfile=setup.cfg
-depends = py{36,37}
 
 [testenv:lint]
 deps = flake8
 skipsdist = true
-commands = flake8 ./src/eyed3
+commands = flake8 ./eyed3
 
 [testenv:check-manifest]
 deps = check-manifest