diff --git a/.travis.yml b/.travis.yml
index fc95f59..949bb2a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,13 @@
 sudo: required
-dist: trusty
+dist: xenial
 language: python
 python:
  - "2.7"
  - "3.4"
  - "3.5"
  - "3.6"
+ - "3.7"
+ - "3.8"
 env:
  - TASKWARRIOR=v2.5.0
  - TASKWARRIOR=v2.5.1
@@ -21,7 +23,7 @@ before_install:
   - task --version
   - cd ../
 install: python setup.py install
-script: python setup.py test
+script: python setup.py nosetests
 notifications:
   email: true
   irc:
diff --git a/taskw/warrior.py b/taskw/warrior.py
index 62c15b1..149d761 100644
--- a/taskw/warrior.py
+++ b/taskw/warrior.py
@@ -447,11 +447,12 @@ def _execute(self, *args):
         command = (
             [
                 'task',
-                'rc:%s' % self.config_filename,
             ]
             + self.get_configuration_override_args()
             + [six.text_type(arg) for arg in args]
         )
+        env = os.environ.copy()
+        env['TASKRC'] = self.config_filename
 
         # subprocess is expecting bytestrings only, so nuke unicode if present
         # and remove control characters
@@ -463,6 +464,7 @@ def _execute(self, *args):
         try:
             proc = subprocess.Popen(
                 command,
+                env=env,
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
             )
diff --git a/test_requirements.txt b/test_requirements.txt
index 9fde877..1600305 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,2 +1,2 @@
-nose>=1.3.4,<2
-tox>=1.8.1,<2
+nose
+tox<3
diff --git a/tox.ini b/tox.ini
index 24534fa..1883ea4 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py{27,34,35,36}-tw{250,251}
+envlist = py{27,34,35,36,37,38}-tw{250,251}
 downloadcache = {toxworkdir}/_download/
 
 [testenv]
@@ -8,6 +8,8 @@ basepython =
     py34: python3.4
     py35: python3.5
     py36: python3.6
+    py37: python3.7
+    py38: python3.8
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test_requirements.txt