In WebDriver tests, sometimes the last visible window is closed by issuing the "Delete Session"[1] when leaving the test fixture. This makes the MiniBrowser's "webViewClose" callback to be called, which currently[2] only removes the target webview from the table of currently open webviews. This behavior might leave the browser in a state where there's no open windows, but the application is still alive.

In some WebDriver tests, this seems to make the WPEWebDriver's Session think there is still an AutomationSession alive on the other side and send commands to it, leading the issued commands to hang. More specifically, when closing the browsing contexts[3], if a connection is still "alive", it'll try to issue getWindowHandles[3] on a deleted session as part of the "close-window" algorithm, it seems.

Note: There is another deadlock issue in selenium related to its webserver using non-daemon threads, which should be fixed by bumping - in a separate bug -the imported suite to include an upstream workaround[4].

Patch for both cases are on the way.

[1] https://www.w3.org/TR/webdriver/#delete-session
[2] https://github.com/WebKit/WebKit/blob/dfd1f46364b965f5c2a578e8375a2709e8c6a55f/Tools/MiniBrowser/wpe/main.cpp#L159
[3] https://github.com/WebKit/WebKit/blob/dfd1f46364b965f5c2a578e8375a2709e8c6a55f/Source/WebDriver/Session.cpp#L534
[4] https://github.com/SeleniumHQ/selenium/commit/d6d672cd93c5cfe57e84c0b17d907bdfd7a3ea2a