switch to disable virtualenvs

pipenv/environments.py

@@ -26,7 +26,7 @@ PIPENV_MAX_DEPTH = int(os.environ.get('PIPENV_MAX_DEPTH', '3')) + 1
 PIPENV_DEFAULT_THREE = os.environ.get('PIPENV_DEFAULT_THREE')
 
 # Tells Pipenv to use the virtualenv-provided pip instead.
-PIPENV_USE_SYSTEM = os.environ.get('VIRTUAL_ENV')
+PIPENV_USE_SYSTEM = os.environ.get('VIRTUAL_ENV') if not 'PIPENV_IGNORE_VIRTUALENVS' in os.environ else False
 
 # Use shell compatibility mode when using venv in project mode.
 if PIPENV_VENV_IN_PROJECT:

tests/test_pipenv.py

@@ -10,6 +10,9 @@ from pipenv.cli import (activate_virtualenv, ensure_proper_casing,
     parse_download_fname, parse_install_output, pip_install, pip_download)
 from pipenv.project import Project
 
+# Tell pipenv to ignore activated virtualenvs.
+os.environ['PIPENV_IGNORE_VIRTUALENVS'] = 'True'
+
 
 class TestPipenv():