diff --git a/.travis.yml b/.travis.yml
index 2b8eafc13..89885d08e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,7 @@ before_install:
 
 before_script:
   - 'if [ $TRAVIS_OS_NAME = osx ] ; then ulimit -n 1024 ; fi'
+  - export TOX_TESTENV_PASSENV=TRAVIS
 
 matrix:
   include:
diff --git a/appveyor.yml b/appveyor.yml
index ce2b5998c..2b6b82747 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -24,6 +24,7 @@ install:
 build: off
 
 test_script:
+  - set TOX_TESTENV_PASSENV=APPVEYOR
   # Test env is set by TOXENV env variable
   - tox
 
diff --git a/tools/pip_install.py b/tools/pip_install.py
index 354dce32b..4466729e0 100755
--- a/tools/pip_install.py
+++ b/tools/pip_install.py
@@ -71,6 +71,11 @@ def main(args):
     tools_path = find_tools_path()
     working_dir = tempfile.mkdtemp()
 
+    if os.environ.get('TRAVIS'):
+        # When this script is executed on Travis, the following print will make the log
+        # be folded until the end command is printed (see finally section).
+        print('travis_fold:start:install_certbot_deps')
+
     try:
         test_constraints = os.path.join(working_dir, 'test_constraints.txt')
         all_constraints = os.path.join(working_dir, 'all_constraints.txt')
@@ -89,6 +94,8 @@ def main(args):
         call_with_print('"{0}" -m pip install --constraint "{1}" {2}'
                         .format(sys.executable, all_constraints, ' '.join(args)))
     finally:
+        if os.environ.get('TRAVIS'):
+            print('travis_fold:end:install_certbot_deps')
         shutil.rmtree(working_dir)
 
 
diff --git a/tox.ini b/tox.ini
index 021c23949..71491c34a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,9 +64,6 @@ source_paths =
     tests/lock_test.py
 
 [testenv]
-passenv = 
-    TRAVIS
-    APPVEYOR
 commands =
     {[base]install_and_test} {[base]all_packages}
     python tests/lock_test.py
@@ -176,7 +173,6 @@ whitelist_externals =
     docker
 passenv =
     DOCKER_*
-    TRAVIS
 
 [testenv:nginx_compat]
 commands =
@@ -187,7 +183,6 @@ whitelist_externals =
     docker
 passenv =
     DOCKER_*
-    TRAVIS
 
 [testenv:le_auto_precise]
 # At the moment, this tests under Python 2.7 only, as only that version is
@@ -199,7 +194,6 @@ whitelist_externals =
     docker
 passenv =
     DOCKER_*
-    TRAVIS
 
 [testenv:le_auto_trusty]
 # At the moment, this tests under Python 2.7 only, as only that version is
@@ -212,7 +206,6 @@ whitelist_externals =
     docker
 passenv =
     DOCKER_*
-    TRAVIS
     TRAVIS_BRANCH
 
 [testenv:le_auto_wheezy]