[PATCH] user32/tests: Wait and flush messages after window creation.

[Rémi Bernon]

The window created in the separate thread in test_Input_mouse sometimes
fails to catch the mouse input in time. Waiting and flushing the initial
messages seems to make the issue harder to reproduce.

Signed-off-by: Rémi Bernon <rbernon(a)codeweavers.com>
---

Notes:
    This is hard to reproduce even without the patch, and it seems to
    only happen on the w1064v1809_ar VM for some reason.

    These runs where started with the original test_Input_mouse code:
    https://testbot.winehq.org/JobDetails.pl?Key=59109 (3 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59110 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59111 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59112 (3 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59127 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59128 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59129 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59130 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59131 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59132 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59145 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59146 (3 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59147 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59148 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59149 (3 failures)

    These runs with the patched version:
    https://testbot.winehq.org/JobDetails.pl?Key=59113 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59114 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59115 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59116 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59121 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59122 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59123 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59124 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59125 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59126 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59140 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59141 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59142 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59143 (0 failures)
    https://testbot.winehq.org/JobDetails.pl?Key=59144 (0 failures)

 dlls/user32/tests/input.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dlls/user32/tests/input.c b/dlls/user32/tests/input.c
index 1e6be311eeb..d0e76038115 100644
--- a/dlls/user32/tests/input.c
+++ b/dlls/user32/tests/input.c
@@ -2196,6 +2196,7 @@ static DWORD WINAPI create_static_win(void *arg)
 {
     struct thread_data *thread_data = arg;
     HWND win;
+    MSG msg;

     win = CreateWindowA("static", "static", WS_VISIBLE | WS_POPUP,
             100, 100, 100, 100, 0, NULL, NULL, NULL);
@@ -2204,6 +2205,7 @@ static DWORD WINAPI create_static_win(void *arg)
             GWLP_WNDPROC, (LONG_PTR)static_hook_proc);
     thread_data->win = win;

+    while (wait_for_message(&msg)) DispatchMessageA(&msg);
     SetEvent(thread_data->start_event);
     wait_for_event(thread_data->end_event, 5000);
     return 0;
--
2.24.0.rc2