use self.delete and add test

qutebrowser/misc/sessions.py

@@ -475,8 +475,6 @@ class SessionManager(QObject):
         old_windows = list(objreg.window_registry.values())
         try:
             self.load(name, temp=temp)
-            if delete:
-                self.session_delete(name)
         except SessionNotFoundError:
             raise cmdexc.CommandError("Session {} not found!".format(name))
         except SessionError as e:
@@ -486,6 +484,17 @@ class SessionManager(QObject):
             if clear:
                 for win in old_windows:
                     win.close()
+            if delete:
+                try:
+                    self.delete(name)
+                except SessionError as e:
+                    log.sessions.exception("Error while deleting session!")
+                    raise cmdexc.CommandError(
+                        "Error while deleting session: {}"
+                        .format(e))
+                else:
+                    log.sessions.debug(
+                        "Loaded & deleted session {}.".format(name))
 
     @cmdutils.register(instance='session-manager')
     @cmdutils.argument('name', completion=miscmodels.session)

tests/end2end/features/sessions.feature

@@ -363,6 +363,16 @@ Feature: Saving and loading sessions
     And I replace "about:blank" by "http://localhost:(port)/data/numbers/2.txt" in the "loaded_session" session file
     And I run :session-load loaded_session
     Then data/numbers/2.txt should be loaded
+  
+  @qtwebengine_flaky
+  Scenario: Loading and deleting a session
+    When I open about:blank
+    And I run :session-save loaded_session
+    And I replace "about:blank" by "http://localhost:(port)/data/numbers/2.txt" in the "loaded_session" session file
+    And I run :session-load --delete loaded_session
+    And I wait for "Loaded & deleted session loaded_session." in the log
+    Then data/numbers/2.txt should be loaded
+    And the session loaded_session should not exist
 
   Scenario: Loading a session which doesn't exist
     When I run :session-load inexistent_session