Fix the Pipfile + setup.py tests

Apparently testing to import the package will work no matter what as we
will find it locally so setup.py may not need to run. By adding a small
dependency I could check if the dependency is installed and now the
tests actually tests what they should.

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

@@ -8,5 +8,5 @@ setup(
     author_email='dummy@my-email.com',
     description='Dummy package for testing purposes only',
     packages=find_packages(),
-    install_requires=['numpy'],
+    install_requires=['pypi-pkg-test==0.0.4'],
 )

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

@@ -1,3 +1,6 @@
 #!/usr/bin/env python
 import there
 import dummy
+
+# This package should be available, as it was a dependency for dummy
+import pypi_pkg_test

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

@@ -8,5 +8,5 @@ setup(
     author_email='dummy@my-email.com',
     description='Dummy package for testing purposes only',
     packages=find_packages(),
-    install_requires=['numpy'],
+    install_requires=['pypi-pkg-test==0.0.4'],
 )

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

@@ -3,7 +3,9 @@ import there
 
 try:
     import dummy
+    import pypi_pkg_test
 except ImportError:
+    # We want an ImportError to be thrown for this test to pass
     pass
 else:
-    raise Exception("'dummy' shouldn't have been installed from setup.py when a Pipfile was present")
+    raise Exception("'dummy' and its dependency 'pypi_pkg_test' shouldn't have been installed! A Pipfile was present without explicit instructions to install the local package 'dummy'.")