From 654a3cc4194084870f762da6c04af59a85741c2c Mon Sep 17 00:00:00 2001 From: Jeffrey Lyon Date: Fri, 8 May 2026 12:59:31 -0700 Subject: [PATCH] gh-149496: Fix MacOSTest.test_default failing when BROWSER env var is set MacOSTest.test_default calls webbrowser.get() and asserts it returns a MacOS instance. When BROWSER is set in the environment (e.g. BROWSER=open, a common macOS workaround for the old osascript-based implementation), register_standard_browsers() registers a GenericBrowser as the preferred browser instead, causing the assertion to fail. This is a regression introduced in gh-137586, which added MacOSTest and moved test_default into it from MacOSXOSAScriptTest. MacOSXOSAScriptTest had an identical setUp() guard added in gh-131254 specifically to fix this same failure. The guard was not carried over to MacOSTest. Add setUp() to MacOSTest to unset BROWSER for the duration of each test, restoring the isolation that was already established as the correct pattern for macOS webbrowser tests. --- Lib/test/test_webbrowser.py | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Lib/test/test_webbrowser.py b/Lib/test/test_webbrowser.py index 51d627d24c5a8a..82f14ca968f266 100644 --- a/Lib/test/test_webbrowser.py +++ b/Lib/test/test_webbrowser.py @@ -340,6 +340,10 @@ def close(self): @requires_subprocess() class MacOSTest(unittest.TestCase): + def setUp(self): + env = self.enterContext(os_helper.EnvironmentVarGuard()) + env.unset("BROWSER") + def test_default(self): browser = webbrowser.get() self.assertIsInstance(browser, webbrowser.MacOS)