diff --git a/.travis.yml b/.travis.yml
index 1e709ba05..6f00324ed 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,12 +18,12 @@ env:
     - TOXENV=py27-xdist
     - TOXENV=py27-trial
     - TOXENV=py27-numpy
-    - TOXENV=py27-pluggymaster
+    - TOXENV=py27-pluggymaster PYTEST_NO_COVERAGE=1
     - TOXENV=py36-pexpect
     - TOXENV=py36-xdist
     - TOXENV=py36-trial
     - TOXENV=py36-numpy
-    - TOXENV=py36-pluggymaster
+    - TOXENV=py36-pluggymaster PYTEST_NO_COVERAGE=1
     - TOXENV=py27-nobyte
     - TOXENV=doctesting
     - TOXENV=docs PYTEST_NO_COVERAGE=1
diff --git a/appveyor.yml b/appveyor.yml
index 949397d3b..7e2c16561 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -13,10 +13,12 @@ environment:
   - TOXENV: "py27-trial"
   - TOXENV: "py27-numpy"
   - TOXENV: "py27-pluggymaster"
+    PYTEST_NO_COVERAGE: "1"
   - TOXENV: "py36-xdist"
   - TOXENV: "py36-trial"
   - TOXENV: "py36-numpy"
   - TOXENV: "py36-pluggymaster"
+    PYTEST_NO_COVERAGE: "1"
   - TOXENV: "py27-nobyte"
   - TOXENV: "doctesting"
   - TOXENV: "py36-freeze"
diff --git a/testing/code/test_code.py b/testing/code/test_code.py
index d1ae648c8..a144bc80e 100644
--- a/testing/code/test_code.py
+++ b/testing/code/test_code.py
@@ -1,13 +1,19 @@
 # coding: utf-8
 from __future__ import absolute_import, division, print_function
+
 import sys
 
 import _pytest._code
 import pytest
-import mock
-from test_excinfo import TWMock
 from six import text_type
 
+from test_excinfo import TWMock
+
+try:
+    import mock
+except ImportError:
+    import unittest.mock as mock
+
 
 def test_ne():
     code1 = _pytest._code.Code(compile('foo = "bar"', "", "exec"))
diff --git a/tox.ini b/tox.ini
index c7ab4f7a5..452bdc60d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -30,7 +30,7 @@ setenv =
 deps =
     hypothesis>=3.56
     nose
-    mock
+    {py27,pypy}: mock
     requests
     {env:_PYTEST_TOX_EXTRA_DEP:}
 
@@ -38,7 +38,7 @@ deps =
 changedir = .
 deps =
     pytest-xdist>=1.13
-    mock
+    py27: mock
     nose
 passenv = USER USERNAME TRAVIS
 commands =
@@ -54,7 +54,7 @@ commands = pre-commit run --all-files --show-diff-on-failure
 [testenv:py27-xdist]
 deps =
     pytest-xdist>=1.13
-    mock
+    {py27,pypy}: mock
     nose
     hypothesis>=3.56
     {env:_PYTEST_TOX_EXTRA_DEP:}
@@ -64,7 +64,13 @@ commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -n auto -ra {posargs:testing}
 
 [testenv:py36-xdist]
-deps = {[testenv:py27-xdist]deps}
+# NOTE: copied from above due to https://github.com/tox-dev/tox/issues/706.
+deps =
+    pytest-xdist>=1.13
+    {py27,pypy}: mock
+    nose
+    hypothesis>=3.56
+    {env:_PYTEST_TOX_EXTRA_DEP:}
 commands = {[testenv:py27-xdist]commands}
 
 [testenv:py27-pexpect]
@@ -87,7 +93,7 @@ commands = {[testenv:py27-pexpect]commands}
 deps =
     pytest-xdist>=1.13
     hypothesis>=3.56
-    mock
+    py27: mock
     {env:_PYTEST_TOX_EXTRA_DEP:}
 distribute = true
 changedir=testing
@@ -127,13 +133,11 @@ commands = {[testenv:py27-numpy]commands}
 setenv=
     {[testenv]setenv}
     _PYTEST_SETUP_SKIP_PLUGGY_DEP=1
-deps =
-    {[testenv]deps}
-    git+https://github.com/pytest-dev/pluggy.git@master
+    # NOTE: using env instead of "{[testenv]deps}", because of https://github.com/tox-dev/tox/issues/706.
+    _PYTEST_TOX_EXTRA_DEP=git+https://github.com/pytest-dev/pluggy.git@master
 
 [testenv:py36-pluggymaster]
 setenv = {[testenv:py27-pluggymaster]setenv}
-deps = {[testenv:py27-pluggymaster]deps}
 
 [testenv:docs]
 skipsdist = True