Add test for Pipfile + setup.py

We want to ignore the setup.py file if it is around along with a
Pipfile.

tests/venv/pipfile/setup-py-implicit/Pipfile

@@ -0,0 +1,7 @@
+[[source]]
+url = "https://pypi.python.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+there = "*"

tests/venv/pipfile/setup-py-implicit/README.rst

@@ -0,0 +1,5 @@
+Python - Pipfile + setup.py
+---------------------------
+
+The Pipfile did not ask for the local package to be installed with ``setup.py``,
+so lets ensure it wasn't.

tests/venv/pipfile/setup-py-implicit/dummy/__init__.py

@@ -0,0 +1,2 @@
+def dummy():
+    pass

tests/venv/pipfile/setup-py-implicit/setup.py

@@ -0,0 +1,12 @@
+from setuptools import setup, find_packages
+
+setup(
+    name='Dummy',
+    version='1.0.0',
+    url='https://git-place.org/dummy/dummy.git',
+    author='Dummy Name',
+    author_email='dummy@my-email.com',
+    description='Dummy package for testing purposes only',
+    packages=find_packages(),
+    install_requires=['numpy'],
+)

tests/venv/pipfile/setup-py-implicit/verify

@@ -0,0 +1,9 @@
+#!/usr/bin/env python
+import there
+
+try:
+    import dummy
+except ImportError:
+    pass
+else:
+    raise Exception("'dummy' shouldn't have been installed from setup.py when a Pipfile was present")