[SHELL32][SHELL32_APITEST][SDK] Implement SHSetUnreadMailCountW (#7620)

Implementing missing features...
JIRA issue: CORE-19278
- Move function definition from
  stubs.cpp into utils.cpp.
- Add prototype to <shellapi.h>.

modules/rostests/apitests/shell32/CMakeLists.txt

@@ -45,6 +45,7 @@ list(APPEND SOURCE
     SHGetAttributesFromDataObject.cpp
     SHGetUserDisplayName.cpp
     SHLimitInputEdit.cpp
+    SHSetUnreadMailCountW.cpp
     menu.cpp
     shelltest.cpp)
 

modules/rostests/apitests/shell32/SHSetUnreadMailCountW.cpp

@@ -0,0 +1,58 @@
+/*
+ * PROJECT:     ReactOS API tests
+ * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
+ * PURPOSE:     Test for SHSetUnreadMailCountW
+ * COPYRIGHT:   Copyright 2025 Katayama Hirofumi MZ (katayama.hirofumi.mz@gmail.com)
+ */
+
+#include "shelltest.h"
+
+START_TEST(SHSetUnreadMailCountW)
+{
+    HKEY hKey;
+    LSTATUS error;
+    DWORD dwDisposition;
+    error = RegCreateKeyExW(HKEY_CURRENT_USER,
+                            L"Software\\Microsoft\\Windows\\CurrentVersion\\UnreadMail\\example.com",
+                            0, NULL, 0, KEY_WRITE, NULL, &hKey, &dwDisposition);
+    ok_long(error, ERROR_SUCCESS);
+    RegCloseKey(hKey);
+
+    HRESULT hr = SHSetUnreadMailCountW(L"example.com", 1, L"MyMailerApp");
+    ok_hex(hr, S_OK);
+
+    error = RegOpenKeyExW(HKEY_CURRENT_USER,
+                          L"Software\\Microsoft\\Windows\\CurrentVersion\\UnreadMail\\example.com",
+                          0,
+                          KEY_READ,
+                          &hKey);
+    ok_long(error, ERROR_SUCCESS);
+
+    DWORD dwValue, cbValue = sizeof(dwValue);
+    error = RegQueryValueExW(hKey, L"MessageCount", NULL, NULL, (PBYTE)&dwValue, &cbValue);
+    ok_long(error, ERROR_SUCCESS);
+    ok_long(dwValue, 1);
+
+    FILETIME FileTime;
+    cbValue = sizeof(FileTime);
+    error = RegQueryValueExW(hKey, L"TimeStamp", NULL, NULL, (PBYTE)&FileTime, &cbValue);
+    ok_long(error, ERROR_SUCCESS);
+    ok(FileTime.dwHighDateTime != 0, "FileTime.dwHighDateTime was zero\n");
+
+    WCHAR szValue[MAX_PATH];
+    cbValue = sizeof(szValue);
+    error = RegQueryValueExW(hKey, L"Application", NULL, NULL, (PBYTE)szValue, &cbValue);
+    ok_long(error, ERROR_SUCCESS);
+    ok_wstr(szValue, L"MyMailerApp");
+
+    RegCloseKey(hKey);
+
+    hr = SHSetUnreadMailCountW(L"example.com", 0, L"MyMailerApp");
+    ok_hex(hr, S_OK);
+
+    if (dwDisposition == REG_CREATED_NEW_KEY)
+    {
+        RegDeleteKeyW(HKEY_CURRENT_USER,
+                      L"Software\\Microsoft\\Windows\\CurrentVersion\\UnreadMail\\example.com");
+    }
+}

modules/rostests/apitests/shell32/testlist.c

@@ -49,6 +49,7 @@ extern void func_SHParseDisplayName(void);
 extern void func_SHShouldShowWizards(void);
 extern void func_SHSimpleIDListFromPath(void);
 extern void func_SHRestricted(void);
+extern void func_SHSetUnreadMailCountW(void);
 
 const struct test winetest_testlist[] =
 {
@@ -98,6 +99,7 @@ const struct test winetest_testlist[] =
     { "SHShouldShowWizards", func_SHShouldShowWizards },
     { "SHSimpleIDListFromPath", func_SHSimpleIDListFromPath },
     { "SHRestricted", func_SHRestricted },
+    { "SHSetUnreadMailCountW", func_SHSetUnreadMailCountW },
 
     { 0, 0 }
 };