Added appcontext_pushed and appcontext_popped signals

docs/signals.rst

@@ -291,6 +291,45 @@ The following signals exist in Flask:
    This will also be passed an `exc` keyword argument that has a reference
    to the exception that caused the teardown if there was one.
 
+.. data:: flask.appcontext_pushed
+   :noindex:
+
+   This signal is sent when an application context is pushed.  The sender
+   is the application.  This is usually useful for unittests in order to
+   temporarily hook in information.  For instance it can be used to
+   set a resource early onto the `g` object.
+
+   Example usage::
+
+        from contextlib import contextmanager
+        from flask import appcontext_pushed
+
+        @contextmanager
+        def user_set(app, user):
+            def handler(sender, **kwargs):
+                g.user = user
+            with appcontext_pushed.connected_to(handler, app):
+                yield
+
+   And in the testcode::
+
+        def test_user_me(self):
+            with user_set(app, 'john'):
+                c = app.test_client()
+                resp = c.get('/users/me')
+                assert resp.data == 'username=john'
+
+   .. versionadded:: 0.10
+
+.. data:: appcontext_popped
+
+   This signal is sent when an application context is popped.  The sender
+   is the application.  This usually falls in line with the
+   :data:`appcontext_tearing_down` signal.
+
+   .. versionadded:: 0.10
+
+
 .. data:: flask.message_flashed
    :noindex: