[BB-2132] [YONK-1560] Support JWT creation on openedx ironwood (#27)

* Support JWT creation on openedx ironwood

Problem root cause: JwtBuilder class was removed in commit dc56a63e of edx-platform
git repository and the eoc-journal xblock was not updated accordingly.

This patch drops support of all openedx versions before ironwood.

* Set pdfminer version in Python requirements for test environment

pdfminer 20140328 is the last version to support Python 2, used by
EDX platform. Due to this, pdfminer newer versions (20091010 and later)
were breaking the tests.

* Fix tests broken by openedx import

An import of Python package openedx was added in commit 4507e0d, but
the test environment does not have that Python package. To avoid
breaking the tests, this patch:

- ignores the import error in Pylint check.
- move the import to inside the function, which is not called in tests
  because the methods which call it are already mocked

* Create a Python module which contains edx-platform dependent code

* Version bump

eoc_journal/compat.py

@@ -0,0 +1,14 @@
+"""
+edx-platform dependent code
+"""
+# pylint: disable=import-error
+
+
+def create_jwt_for_user(user):
+    """
+    Wraps openedx.core.djangoapps.oauth_dispatch.jwt.create_jwt_for_user() call
+    """
+    # test env does not have edx-platform installed. because of this, all edx-platform imports must be
+    # kept inside this function so that the test code does not break when importing the module
+    from openedx.core.djangoapps.oauth_dispatch.jwt import create_jwt_for_user as openedx_create_jwt_for_user
+    return openedx_create_jwt_for_user(user)

eoc_journal/utils.py

@@ -2,10 +2,7 @@
 
 from edx_rest_api_client.client import EdxRestApiClient
 
-try:
-    from openedx.core.lib.token_utils import JwtBuilder  # pylint: disable=F0401
-except ImportError:
-    JwtBuilder = None  # pylint: disable=C0103
+from .compat import create_jwt_for_user
 
 
 def normalize_id(key):
@@ -31,9 +28,8 @@ def build_jwt_edx_client(url, scopes, user, expires_in, append_slash=True):
     """
     Returns an edx API client authorized using JWT.
     """
-    if JwtBuilder is None:
-        raise NotConnectedToOpenEdX("This package must be installed in an OpenEdX environment.")
-    jwt = JwtBuilder(user).build_token(scopes, expires_in)
+
+    jwt = create_jwt_for_user(user)
     return EdxRestApiClient(url, append_slash=append_slash, jwt=jwt)
 
 

requirements-test.txt

@@ -13,7 +13,7 @@ fs
 lxml
 mako
 markupsafe
-pdfminer
+pdfminer==20140328
 pycodestyle
 pylint
 python-dateutil

setup.py

@@ -22,7 +22,7 @@ def package_data(pkg, roots):
 
 setup(
     name='xblock-eoc-journal',
-    version='0.4',
+    version='0.5',
     description='End of Course Journal XBlock',
     packages=[
         'eoc_journal',