Fixture closure is now correctly updated after append. Fixes #176

pytest_cases/plugin.py

@@ -487,10 +487,13 @@ def __init__(self,
 
         # save the fixture closure tree root
         self.tree = root_node
+        # retrieve/sort fixture defs for quicker access
+        self._update_fixture_defs()
 
+    def _update_fixture_defs(self):
         # get a list of all fixture defs, for quicker access (and sorted)
         # sort by scope as in pytest fixture closure creator, if scope information is available
-        all_fixture_defs = root_node.get_all_fixture_defs(drop_fake_fixtures=False, try_to_sort=True)
+        all_fixture_defs = self.tree.get_all_fixture_defs(drop_fake_fixtures=False, try_to_sort=True)
 
         # # also sort all partitions (note that we cannot rely on the order in all_fixture_defs when scopes are same!)
         # if LooseVersion(pytest.__version__) >= LooseVersion('3.5.0'):
@@ -581,6 +584,8 @@ def insert(self, index, fixture_name):
         if index == len(self):
             # append: supported
             self.tree.build_closure((fixture_name,))
+            # update fixture defs
+            self._update_fixture_defs()
         else:
             raise NotImplementedError("When fixture unions are present, inserting a fixture in the closure is "
                                       "non-trivial. Please report this so that we can find a suitable solution for "

pytest_cases/tests/pytest_extension/fixtures/fixture_unions/test_fixture_closure_edits.py

@@ -59,8 +59,9 @@ def test_super_closure_edits2():
     with pytest.raises(NotImplementedError):
         del super_closure[-1]
 
-    with pytest.raises(NotImplementedError):
-        super_closure.append('toto')
+    # now supported
+    super_closure.append('toto')
+    assert list(super_closure) == ['environment', 'a', 'request', 'b', 'toto']
 
     with pytest.raises(NotImplementedError):
         super_closure.insert(0, 'toto')