jupyter#751 adding widget metadata moved to separate method

ipywidgets min version changed to 7

nbconvert/preprocessors/execute.py

@@ -358,6 +358,23 @@ def preprocess(self, nb, resources, km=None):
 
         return nb, resources
 
+    def set_widgets_metadata(self):
+        if self.widget_state:
+            self.nb.metadata.widgets = {
+                'application/vnd.jupyter.widget-state+json': {
+                    'state': {
+                        model_id: _serialize_widget_state(state)
+                        for model_id, state in self.widget_state.items() if '_model_name' in state
+                    },
+                    'version_major': 2,
+                    'version_minor': 0,
+                }
+            }
+            for key, widget in self.nb.metadata.widgets['application/vnd.jupyter.widget-state+json']['state'].items():
+                buffers = self.widget_buffers.get(key)
+                if buffers:
+                    widget['buffers'] = buffers
+
     def preprocess_cell(self, cell, resources, cell_index):
         """
         Executes a single code cell. See base.py for details.

setup.py

@@ -213,7 +213,7 @@ def run(self):
 jupyter_client_req = 'jupyter_client>=4.2'
 
 extra_requirements = {
-(??)    'test': ['pytest', 'pytest-cov', 'ipykernel', 'jupyter_client>=4.2'],
+    'test': ['pytest', 'pytest-cov', 'ipykernel', 'jupyter_client>=4.2', 'ipywidgets>=7'],
     'serve': ['tornado>=4.0'],
     'execute': [jupyter_client_req],
     'docs': ['sphinx>=1.5.1',