Collect and aggregate code coverage across all test environments (#460)

* Collect and aggregate code coverage across all test environments

Add Coveralls badge to readme

Try CodeCov integration

Setup coverage badge for CodeCov

Fix CodeCov Badge

* Set code coverage regression threshold

Attempt to cache bust some boto3 issues on TravisCI

* Disable legacy secure strings

* Skip boto3 tests on TRAVIS_PULL_REQUEST due to credentials being unavailable

Address flake8 issues

Debug TRAVIS_PULL_REQUEST ENV Var

Trying to get boto3 tests to skip on forked PRs

boto3 is not an allowed failure

remove TRAVIS ENV debugging

* remove pytest skipif that wasn't working

* Ignore coverage files

tox.ini

@@ -1,5 +1,21 @@
 [tox]
-envlist = {py27,py35,py36,py37,pypy}-{flakes,requests,httplib2,urllib3,tornado4,boto3},{py35,py36,py37}-{aiohttp}
+skip_missing_interpreters=true
+envlist = cov-clean,{py27,py35,py36,py37,pypy}-{flakes,requests,httplib2,urllib3,tornado4,boto3},{py35,py36,py37}-{aiohttp},cov-report
+
+
+# Coverage environment tasks: cov-clean and cov-report
+# https://pytest-cov.readthedocs.io/en/latest/tox.html
+[testenv:cov-clean]
+deps = coverage
+skip_install=true
+commands = coverage erase
+
+[testenv:cov-report]
+deps = coverage
+skip_install=true
+commands = 
+  coverage html
+  coverage report --fail-under=75
 
 [testenv:flakes]
 skipsdist = True
@@ -10,8 +26,11 @@ commands =
 deps = flake8
 
 [testenv]
+# Need to use develop install so that paths
+# for aggregate code coverage combine
+usedevelop=true
 commands =
-    ./runtests.sh --cov={envsitepackagesdir}/vcr --cov-branch {posargs}
+    ./runtests.sh --cov=./vcr --cov-branch --cov-report=xml --cov-append {posargs}
 deps =
     Flask
     mock
@@ -31,9 +50,13 @@ deps =
     aiohttp: aiohttp
     aiohttp: pytest-asyncio
     aiohttp: pytest-aiohttp
+depends = 
+  {py27,py35,py36,py37,pypy}-{flakes,requests,httplib2,urllib3,tornado4,boto3},{py35,py36,py37}-{aiohttp}: cov-clean
+  cov-report: {py27,py35,py36,py37,pypy}-{flakes,requests,httplib2,urllib3,tornado4,boto3},{py35,py36,py37}-{aiohttp}
 passenv =
     AWS_ACCESS_KEY_ID
     AWS_DEFAULT_REGION
     AWS_SECRET_ACCESS_KEY
+
 [flake8]
 max_line_length = 110