[PATCH 1/2] user32/tests: Add more SendMessageCallbackA/W() tests with NULL callback.

[Zhiyi Zhang]

From: Zhiyi Zhang

The tests are mainly to show that SendMessageCallbackA/W() with NULL callback pointer and callback
data being 1 causes message to be posted to window, even when the window is created in the same thread.
---
 dlls/user32/tests/msg.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 80d900baa1c..1c2d61c7781 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -16499,6 +16499,12 @@ static void test_EndDialog(void)
     UnregisterClassA(cls.lpszClassName, cls.hInstance);
 }

+static const struct message WmUserSeq[] =
+{
+    { WM_USER, sent },
+    { 0 }
+};
+
 static void test_nullCallback(void)
 {
     HWND hwnd;
@@ -16507,8 +16513,39 @@ static void test_nullCallback(void)
                            100, 100, 200, 200, 0, 0, 0, NULL);
     ok (hwnd != 0, "Failed to create overlapped window\n");

-    SendMessageCallbackA(hwnd,WM_NULL,0,0,NULL,0);
+    /* NULL callback and data being 0 */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 0);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 0);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    /* NULL callback and data being 1. The result suggests that the message is posted to the window */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 1);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
     flush_events();
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+
+    /* NULL callback and data being 1. The result suggests that the message is posted to the window */
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 1);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
+    flush_events();
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+
+    /* NULL callback and data being 2 */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 2);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    /* NULL callback and data being 2 */
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 2);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
     DestroyWindow(hwnd);
 }