test: add empty context test

Author: rpenido

xblock/test/test_field_data.py

@@ -40,6 +40,11 @@ def setup_method(self):
             Scope.content: self.content,
             Scope.settings: self.settings
         })
+        self.split_empty = SplitFieldData({
+            Scope.content: self.content,
+            Scope.settings: self.settings,
+            Scope.user_state: None,
+        })
         self.runtime = TestRuntime(services={'field-data': self.split})
         self.block = TestingBlock(
             runtime=self.runtime,
@@ -76,6 +81,18 @@ def test_invalid_scope(self):
         with pytest.raises(InvalidScopeError):
             self.split.get(self.block, 'user_state')
 
+    def test_empty_scope(self):
+        with pytest.raises(InvalidScopeError):
+            self.split_empty.get(self.block, 'user_state')
+
+    def test_empty_scope_set_many(self):
+        self.split_empty.set_many(
+            self.block,
+            {'content': 'new content', 'settings': 'new settings', 'user_state': 'new user state'},
+        )
+        self.content.set_many.assert_called_once_with(self.block, {'content': 'new content'})
+        self.settings.set_many.assert_called_once_with(self.block, {'settings': 'new settings'})
+
     def test_default(self):
         self.split.default(self.block, 'content')
         self.content.default.assert_called_once_with(self.block, 'content')