diff --git a/pipenv/environments.py b/pipenv/environments.py
index eaf0be55..a8745a9a 100644
--- a/pipenv/environments.py
+++ b/pipenv/environments.py
@@ -13,6 +13,9 @@ PIPENV_SHELL_FANCY = bool(os.environ.get('PIPENV_SHELL_FANCY'))
 # Create the virtualenv in the project, instead of with pew.
 PIPENV_VENV_IN_PROJECT = bool(os.environ.get('PIPENV_VENV_IN_PROJECT')) or os.path.isdir('.venv')
 
+# Overwrite all index funcitonality.
+PIPENV_TEST_INDEX = os.environ.get('PIPENV_TEST_INDEX')
+
 # No color mode, for unfun people.
 PIPENV_COLORBLIND = bool(os.environ.get('PIPENV_COLORBLIND'))
 
diff --git a/pipenv/project.py b/pipenv/project.py
index a1f0c790..5634b762 100644
--- a/pipenv/project.py
+++ b/pipenv/project.py
@@ -23,7 +23,8 @@ from .environments import (
     PIPENV_PIPFILE,
     PIPENV_VENV_IN_PROJECT,
     PIPENV_VIRTUALENV,
-    PIPENV_NO_INHERIT
+    PIPENV_NO_INHERIT,
+    PIPENV_TEST_INDEX
 )
 
 if PIPENV_PIPFILE:
@@ -410,17 +411,20 @@ class Project(object):
         install = dict(config_parser.get_config_section('install'))
         indexes = install.get('extra-index-url', '').lstrip('\n').split('\n')
 
-        # Default source.
-        pypi_source = {u'url': u'https://pypi.python.org/simple', u'verify_ssl': True, u'name': 'pypi'}
-        sources = [pypi_source]
+        if PIPENV_TEST_INDEX:
+            sources = [{u'url': PIPENV_TEST_INDEX, u'verify_ssl': True, u'name': u'custom'}]
+        else:
+            # Default source.
+            pypi_source = {u'url': u'https://pypi.python.org/simple', u'verify_ssl': True, u'name': 'pypi'}
+            sources = [pypi_source]
 
-        for i, index in enumerate(indexes):
-            if not index:
-                continue
-            source_name = 'pip_index_{}'.format(i)
-            verify_ssl = index.startswith('https')
+            for i, index in enumerate(indexes):
+                if not index:
+                    continue
+                source_name = 'pip_index_{}'.format(i)
+                verify_ssl = index.startswith('https')
 
-            sources.append({u'url': index, u'verify_ssl': verify_ssl, u'name': source_name})
+                sources.append({u'url': index, u'verify_ssl': verify_ssl, u'name': source_name})
 
         data = {
             u'source': sources,
diff --git a/tests/test_pipenv.py b/tests/test_pipenv.py
index e4ccb070..1870f8c0 100644
--- a/tests/test_pipenv.py
+++ b/tests/test_pipenv.py
@@ -25,6 +25,15 @@ except:
 
 os.environ['PIPENV_DONT_USE_PYENV'] = '1'
 os.environ['PIPENV_IGNORE_VIRTUALENVS'] = '1'
+os.environ['PYPI_VENDOR_DIR'] = os.path.sep.join([os.path.dirname(__file__), 'pypi'])
+
+from flask import Flask
+
+class PYPI(object):
+    """docstring for PYPI"""
+    def __init__(self, packages=None):
+        super(PYPI, self).__init__()
+        self.packages = packages or []
 
 
 @pytest.fixture(scope='module')
@@ -41,7 +50,8 @@ def pip_src_dir(request):
 
 class PipenvInstance():
     """An instance of a Pipenv Project..."""
-    def __init__(self, pipfile=True, chdir=False):
+    def __init__(self, pypi=None, pipfile=True, chdir=False):
+        self.pypi = pypi
         self.original_umask = os.umask(0o007)
         self.original_dir = os.path.abspath(os.curdir)
         self._path = TemporaryDirectory(suffix='project', prefix='pipenv')
@@ -50,6 +60,9 @@ class PipenvInstance():
         self.pipfile_path = None
         self.chdir = chdir
 
+        if self.pypi:
+            os.environ['PIPENV_TEST_INDEX'] = '{0}/simple'.format(self.pypi.url)
+
         if pipfile:
             p_path = os.sep.join([self.path, 'Pipfile'])
             with open(p_path, 'a'):
@@ -111,8 +124,8 @@ class TestPipenv:
     """The ultimate testing class."""
 
     @pytest.mark.cli
-    def test_pipenv_where(self):
-        with PipenvInstance() as p:
+    def test_pipenv_where(self, pypi_secure):
+        with PipenvInstance(pypi=pypi_secure) as p:
             assert normalize_drive(p.path) in p.pipenv('--where').out
 
     @pytest.mark.cli
@@ -137,15 +150,15 @@ class TestPipenv:
             assert not os.path.isdir(venv_path)
 
     @pytest.mark.cli
-    def test_pipenv_graph(self):
-        with PipenvInstance() as p:
+    def test_pipenv_graph(self, pypi):
+        with PipenvInstance(pypi=pypi) as p:
             p.pipenv('install requests')
             assert 'requests' in p.pipenv('graph').out
             assert 'requests' in p.pipenv('graph --json').out
 
     @pytest.mark.cli
-    def test_pipenv_graph_reverse(self):
-        with PipenvInstance() as p:
+    def test_pipenv_graph_reverse(self, pypi):
+        with PipenvInstance(pypi=pypi) as p:
             p.pipenv('install requests==2.18.4')
             output = p.pipenv('graph --reverse').out
 
@@ -168,8 +181,8 @@ class TestPipenv:
             assert 'Warning: Using both --reverse and --json together is not supported.' in c.err
 
     @pytest.mark.cli
-    def test_pipenv_check(self):
-        with PipenvInstance() as p:
+    def test_pipenv_check(self, pypi):
+        with PipenvInstance(pypi=pypi) as p:
             p.pipenv('install requests==1.0.0')
             assert 'requests' in p.pipenv('check').out