Fix pip version changes

Author: Juergen Hasch

appveyor.yml

@@ -59,11 +59,11 @@ install:
   # parent CMD process).
   - "SET PATH=%PYTHON_HOME%;%PYTHON_HOME%\\Scripts;%PATH%"
   # Check that we have the expected version and architecture for Python
-  - "%TOXPYTHON --version"
-  - "%TOXPYTHON% -c \"import struct; print(struct.calcsize('P') * 8)\""
+  - "python --version"
+  - "python -c \"import struct; print(struct.calcsize('P') * 8)\""
   # Upgrade to the latest version of pip to avoid it displaying warnings
   # about it being out of date.
-  - 'pip install --disable-pip-version-check --user --upgrade pip'
+  - 'python -m pip install --disable-pip-version-check --user --upgrade pip'
   # install tox
   - pip install tox
   # install of the actual project is handled by tox in tests

tests/test_migrate.py

@@ -12,6 +12,7 @@
 
 import nose.tools as nt
 import pip
+from pip import __main__
 from jupyter_contrib_core.testing_utils import (
     get_logger, patch_traitlets_app_logs,
 )
@@ -65,7 +66,7 @@ def setUp(self):
     def install_old_pkg(self):
         old_pkg_project_name = self.old_pkg_project_name
         # install old repo version
-        pip.main(['install', '-v', self.get_old_pkg_url()])
+        __main__(['install', '-v', self.get_old_pkg_url()])
         # check pip installed ok
         nt.assert_in(
             old_pkg_project_name, get_installed_project_names(),