Also patch JUPYTER_RUNTIME_DIR env var

in `testing_utils.jupyter_env`

Author: jcb91

README.md

@@ -22,6 +22,8 @@ Changes
 * Get `jupyter contrib` app subcommands from `pkg_resources` entrypoints
 * Add `_maybe_copy` and `_should_copy` to nbextensions private API, since the
   `logger` keyword arg was only added after notebook 4.1
+* Also patch `JUPYTER_RUNTIME_DIR` environment variable in
+  `testing_utils.jupyter_env`
 
 0.2.0
 -----

src/jupyter_contrib_core/testing_utils/jupyter_env.py

@@ -59,6 +59,7 @@ def patch_jupyter_dirs():
             'HOME': jupyter_dirs['user_home']['root'],
             'JUPYTER_CONFIG_DIR': jupyter_dirs['env_vars']['conf'],
             'JUPYTER_DATA_DIR': jupyter_dirs['env_vars']['data'],
+            'JUPYTER_RUNTIME_DIR': jupyter_dirs['server']['runtime'],
         })))
 
     # patch jupyter path variables in various modules