Serialize coverage tests (certbot#3919)

* Serialize coverage tests

* add py27_install env

* Separate cover from integration tests

* Add docker to py27 integration tests

.travis.yml

@@ -17,12 +17,7 @@ env:
 matrix:
   include:
     - python: "2.7"
-      env: TOXENV=cover BOULDER_INTEGRATION=1
-      sudo: required
-      after_failure:
-        - sudo cat /var/log/mysql/error.log
-        - ps aux | grep mysql
-      services: docker
+      env: TOXENV=cover
     - python: "2.7"
       env: TOXENV=lint
     - python: "2.7"
@@ -46,6 +41,13 @@ matrix:
         - sudo cat /var/log/mysql/error.log
         - ps aux | grep mysql
       services: docker
+    - python: "2.7"
+      env: TOXENV=py27_install BOULDER_INTEGRATION=1
+      sudo: required
+      after_failure:
+        - sudo cat /var/log/mysql/error.log
+        - ps aux | grep mysql
+      services: docker
     - sudo: required
       env: TOXENV=apache_compat
       services: docker

tox.cover.sh

@@ -36,9 +36,8 @@ cover () {
   # specific package, positional argument scopes tests only to
   # specific package directory; --cover-tests makes sure every tests
   # is run (c.f. #403)
-  nosetests -c /dev/null --with-cover --cover-tests --cover-package \
-            "$1" --cover-min-percentage="$min" "$1" --processes=-1 \
-            --process-timeout=100
+  nosetests -c /dev/null --with-cover --cover-tests --cover-package  \
+            "$1" --cover-min-percentage="$min" "$1"
 }
 
 rm -f .coverage  # --cover-erase is off, make sure stats are correct

tox.ini

@@ -63,6 +63,11 @@ commands =
     pip install -e .[dev]
     nosetests -v certbot --processes=-1 --process-timeout=100
 
+[testenv:py27_install]
+basepython = python2.7
+commands =
+    pip install -e acme[dns,dev] -e .[dev] -e certbot-apache -e certbot-nginx -e letshelp-certbot
+
 [testenv:cover]
 basepython = python2.7
 commands =