From c9176b7c581162961748b2321c585cd6a21decf3 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <git@the-compiler.org>
Date: Wed, 13 Jul 2016 18:17:37 +0200
Subject: [PATCH] QtWebEngine: Fix 'unset' with run_js_blocking

---
 qutebrowser/browser/webengine/webenginetab.py | 5 +++--
 tests/unit/browser/test_tab.py                | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/qutebrowser/browser/webengine/webenginetab.py b/qutebrowser/browser/webengine/webenginetab.py
index 8a0808408..a03ab24e4 100644
--- a/qutebrowser/browser/webengine/webenginetab.py
+++ b/qutebrowser/browser/webengine/webenginetab.py
@@ -344,8 +344,9 @@ class WebEngineTab(browsertab.AbstractTab):
             self._widget.page().runJavaScript(code, callback)
 
     def run_js_blocking(self, code):
+        unset = object()
         loop = qtutils.EventLoop()
-        js_ret = None
+        js_ret = unset
 
         def js_cb(val):
             """Handle return value from JS and stop blocking."""
@@ -355,7 +356,7 @@ class WebEngineTab(browsertab.AbstractTab):
 
         self.run_js_async(code, js_cb)
         loop.exec_()  # blocks until loop.quit() in js_cb
-        assert js_ret is not None
+        assert js_ret is not unset
 
         return js_ret
 
diff --git a/tests/unit/browser/test_tab.py b/tests/unit/browser/test_tab.py
index 13bdb9169..d325213ed 100644
--- a/tests/unit/browser/test_tab.py
+++ b/tests/unit/browser/test_tab.py
@@ -122,8 +122,9 @@ def test_tab(qtbot, view, config_stub, tab_registry):
 
 class TestJs:
 
-    def test_blocking(self, tab):
-        assert tab.run_js_blocking('1 + 1') == 2
+    @pytest.mark.parametrize('inp, expected', [('1+1', 2), ('undefined', None)])
+    def test_blocking(self, tab, inp, expected):
+        assert tab.run_js_blocking(inp) == expected
 
 
 class TestTabData: