diff --git a/.travis.yml b/.travis.yml
index f5b5f1cc..7b1b70a0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,7 +21,6 @@ matrix:
     - python: 3.7
       env:
         - TOXENV=cov-py37
-        - JEDI_TEST_ENVIRONMENT=37
     # For now ignore pypy, there are so many issues that we don't really need
     # to run it.
     #- python: pypy
diff --git a/test/conftest.py b/test/conftest.py
index b023f185..64bc8be7 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -1,4 +1,5 @@
 import os
+import sys
 import subprocess
 from itertools import count
 
@@ -7,12 +8,19 @@ import pytest
 from . import helpers
 from . import run
 from . import refactor
-from jedi.api.environment import InterpreterEnvironment
+from jedi.api.environment import InterpreterEnvironment, get_system_environment
 from jedi.inference.compiled.value import create_from_access_path
 from jedi.inference.imports import _load_python_module
 from jedi.file_io import KnownContentFileIO
 from jedi.inference.base_value import ValueSet
 
+# For interpreter tests sometimes the path of this directory is in the sys
+# path, which we definitely don't want. So just remove it globally.
+try:
+    sys.path.remove(helpers.test_dir)
+except ValueError:
+    pass
+
 
 def pytest_addoption(parser):
     parser.addoption(
@@ -93,9 +101,15 @@ def collect_static_analysis_tests(base_dir, test_files):
 def venv_path(tmpdir_factory, environment):
     if environment.version_info.major < 3:
         pytest.skip("python -m venv does not exist in Python 2")
+    elif isinstance(environment, InterpreterEnvironment):
+        # The environment can be a tox virtualenv environment which we don't
+        # want, so use the system environment.
+        environment = get_system_environment(
+            '.'.join(str(x) for x in environment.version_info[:2])
+        )
 
     tmpdir = tmpdir_factory.mktemp('venv_path')
-    dirname = os.path.join(tmpdir.dirname, 'venv')
+    dirname = os.path.join(tmpdir.strpath, 'venv')
 
     # We cannot use the Python from tox because tox creates virtualenvs and
     # they have different site.py files that work differently than the default
@@ -113,7 +127,8 @@ def venv_path(tmpdir_factory, environment):
         executable_name = os.path.basename(environment.executable)
         executable_path = os.path.join(prefix, 'bin', executable_name)
 
-    subprocess.call([executable_path, '-m', 'venv', dirname])
+    return_code = subprocess.call([executable_path, '-m', 'venv', dirname])
+    assert return_code == 0, return_code
     return dirname