Compatibility with Sphinx 3.0.0

"The structure of sphinx.events.EventManager.listeners has changed",
from https://www.sphinx-doc.org/en/master/changes.html#release-3-0-0-released-apr-06-2020

Author: humitos

hoverxref/extension.py

@@ -1,6 +1,7 @@
 import os
 import inspect
 from docutils import nodes
+import sphinx
 from sphinx.roles import XRefRole
 from sphinx.util.fileutil import copy_asset
 
@@ -76,7 +77,13 @@ def setup_sphinx_tabs(app, config):
     Sphinx Tabs removes the CSS/JS from pages that does not use the directive.
     Although, we need them to use inside the tooltip.
     """
-    listeners = list(app.events.listeners.get('html-page-context').items())
+    if sphinx.version_info < (3, 0, 0):
+        listeners = list(app.events.listeners.get('html-page-context').items())
+    else:
+        listeners = [
+            (listener.id, listener.handler)
+            for listener in app.events.listeners.get('html-page-context')
+        ]
     for listener_id, function in listeners:
         module_name = inspect.getmodule(function).__name__
         if module_name == 'sphinx_tabs.tabs':

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 envlist =
   docs
-  py{36,37,38}-sphinx{185,201,210,220,231}
+  py{36,37,38}-sphinx{185,201,210,220,231,300}
 
 [testenv]
 deps =
@@ -13,6 +13,7 @@ deps =
   sphinx210: sphinx==2.1.0
   sphinx220: sphinx==2.2.0
   sphinx231: sphinx==2.3.1
+  sphinx300: sphinx==3.0.0
 commands = pytest {posargs}
 
 [testenv:py37-sphinx210]