[USER32_APITEST] Show that scrollbars can be created when extra window data is requested.

modules/rostests/apitests/user32/CMakeLists.txt

@@ -29,6 +29,7 @@ list(APPEND SOURCE
     RedrawWindow.c
     RegisterClassEx.c
     RegisterHotKey.c
+    ScrollBarWndExtra.c
     ScrollDC.c
     ScrollWindowEx.c
     SendMessageTimeout.c

modules/rostests/apitests/user32/ScrollBarWndExtra.c

@@ -0,0 +1,61 @@
+/*
+ * PROJECT:     ReactOS API tests
+ * LICENSE:     LGPL-2.1+ (https://spdx.org/licenses/LGPL-2.1+)
+ * PURPOSE:     Test for ScrollBar cbWndExtra
+ * COPYRIGHT:   Copyright 2019 Mark Jansen <mark.jansen@reactos.org>
+ *
+ * Why do we need this test?
+ * Ask the authors of Civilization II...
+ */
+
+#include "precomp.h"
+
+#define BUILTIN_SCROLLBAR   "Scrollbar"
+#define CUSTOM_SCROLLBAR    "MSScrollBarClass"
+
+
+
+START_TEST(ScrollBarWndExtra)
+{
+    HWND hScrollBar;
+    HWND hScrollBarImpersonator;
+    WNDCLASSA WndClass;
+    ATOM ClassAtom;
+
+    LONG_PTR dummyData = (LONG_PTR)0xbeefbeefbeefbeefULL, result;
+    WNDPROC lpfnWndProc;
+    DWORD dwExtra;
+
+    hScrollBar = CreateWindowExA(0, BUILTIN_SCROLLBAR, "", WS_POPUP,
+                                 20, 20, 120, 120, NULL, 0, GetModuleHandle(NULL), 0);
+
+    ok(hScrollBar != NULL, "Scrollbar creation failed (%lu)\n", GetLastError());
+
+    lpfnWndProc = (WNDPROC)GetWindowLongPtrA(hScrollBar, GWL_WNDPROC);
+    dwExtra = GetClassLongPtrA(hScrollBar, GCL_CBWNDEXTRA);
+
+    ZeroMemory(&WndClass, sizeof(WndClass));
+    WndClass.style = CS_DBLCLKS | CS_PARENTDC | CS_HREDRAW | CS_VREDRAW;
+    WndClass.lpfnWndProc = lpfnWndProc;
+    WndClass.cbWndExtra = dwExtra + sizeof(LONG_PTR);
+    WndClass.hInstance = GetModuleHandle(NULL);
+    WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    WndClass.hbrBackground = GetStockObject(LTGRAY_BRUSH);
+    WndClass.lpszClassName = CUSTOM_SCROLLBAR;
+    ClassAtom = RegisterClassA(&WndClass);
+
+    ok(ClassAtom != 0, "RegisterClassA failed (%lu)\n", GetLastError());
+    DestroyWindow(hScrollBar);
+
+
+    hScrollBarImpersonator = CreateWindowExA(0, CUSTOM_SCROLLBAR, "", WS_POPUP,
+                                             20, 20, 120, 120, NULL, 0, GetModuleHandle(NULL), 0);
+    ok(hScrollBarImpersonator != NULL, "Scrollbar creation failed (%lu)\n", GetLastError());
+
+    SetWindowLongPtrA(hScrollBarImpersonator, dwExtra, dummyData);
+    result = GetWindowLongPtrA(hScrollBarImpersonator, dwExtra);
+    ok(result == dummyData, "Invalid dummyData\n");
+
+    DestroyWindow(hScrollBarImpersonator);
+    UnregisterClassA(CUSTOM_SCROLLBAR, GetModuleHandle(NULL));
+}

modules/rostests/apitests/user32/testlist.c

@@ -31,6 +31,7 @@ extern void func_RealGetWindowClass(void);
 extern void func_RedrawWindow(void);
 extern void func_RegisterHotKey(void);
 extern void func_RegisterClassEx(void);
+extern void func_ScrollBarWndExtra(void);
 extern void func_ScrollDC(void);
 extern void func_ScrollWindowEx(void);
 extern void func_SendMessageTimeout(void);
@@ -76,6 +77,7 @@ const struct test winetest_testlist[] =
     { "RedrawWindow", func_RedrawWindow },
     { "RegisterHotKey", func_RegisterHotKey },
     { "RegisterClassEx", func_RegisterClassEx },
+    { "ScrollBarWndExtra", func_ScrollBarWndExtra },
     { "ScrollDC", func_ScrollDC },
     { "ScrollWindowEx", func_ScrollWindowEx },
     { "SendMessageTimeout", func_SendMessageTimeout },