diff --git a/.coveragerc b/.coveragerc
index 7492b713f..caaf31b37 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -1,4 +1,5 @@
 [run]
+branch = true
 source = stripe
 omit =
     stripe/six.py
diff --git a/.travis.yml b/.travis.yml
index f82d848b6..4075b4230 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,7 @@
 sudo: false
 
+dist: xenial
+
 language: python
 
 matrix:
@@ -9,9 +11,11 @@ matrix:
     - python: "3.5"
     - python: "3.6"
     - python: "3.7"
-      dist: xenial
-    - python: "pypy"
-    - python: "pypy3"
+    - python: "3.8-dev"
+    - python: "pypy2.7-6.0"
+    - python: "pypy3.5-6.0"
+  allow_failures:
+    - python: "3.8-dev"
 
 cache:
   directories:
diff --git a/tox.ini b/tox.ini
index 01f922e77..b9a102a64 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,9 +23,11 @@ description = run code formatting using black
 basepython = python3.7
 deps = black
 commands = black . {posargs}
+skip_install = true
 
 [testenv:lint]
 description = run static analysis and style check using flake8
 basepython = python2.7
 deps = flake8
 commands = python -m flake8 --show-source stripe tests setup.py {posargs}
+skip_install = true