[NTDLL_APITEST] Add a test for LdrFindResource_U / CORE-20401

See CORE-20401, CORE-20408

modules/rostests/apitests/ntdll/CMakeLists.txt

@@ -39,6 +39,7 @@ add_dependencies(ntdll_crt_test_lib psdk)
 list(APPEND SOURCE
     DllLoadNotification.c
     LdrEnumResources.c
+    LdrFindResource_U.c
     LdrLoadDll.c
     load_notifications.c
     locale.c

modules/rostests/apitests/ntdll/LdrFindResource_U.c

@@ -0,0 +1,30 @@
+/*
+ * PROJECT:     ReactOS API tests
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Test for LdrFindResource_U
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include "precomp.h"
+
+static void Test_CORE_20401(void)
+{
+    HMODULE hmod = GetModuleHandleW(NULL);
+    LDR_RESOURCE_INFO info;
+    IMAGE_RESOURCE_DATA_ENTRY *entry = NULL;
+    NTSTATUS Status;
+
+    // Use LdrFindResource_U to find a bitmap resource called "NORMAL_FRAMECAPTION_BMP"
+    // CORE-20401 resulted in wrong comparison of strings containing underscores.
+    // If the test fails, the resource name comparison is probably broken (again).
+    info.Type = 2; // RT_BITMAP;
+    info.Name = (ULONG_PTR)L"NORMAL_FRAMECAPTION_BMP";
+    info.Language = MAKELANGID(LANG_NEUTRAL, SUBLANG_NEUTRAL);
+    Status = LdrFindResource_U(hmod, &info, 3, &entry);
+    ok_ntstatus(Status, STATUS_SUCCESS);
+}
+
+START_TEST(LdrFindResource_U)
+{
+    Test_CORE_20401();
+}

modules/rostests/apitests/ntdll/testdata.rc

@@ -1,3 +1,7 @@
 
 101 10 "load_notifications.dll"
 102 10 "empty_dll.dll"
+
+NORMAL_FRAMECAPTIONMIN BITMAP "bmp1.bmp"
+NORMAL_FRAMECAPTIONMIN_BMP BITMAP "bmp1.bmp"
+NORMAL_FRAMECAPTION_BMP BITMAP "bmp1.bmp"

modules/rostests/apitests/ntdll/testlist.c

@@ -26,6 +26,7 @@ extern void func_wcstombs(void);
 
 extern void func_DllLoadNotification(void);
 extern void func_LdrEnumResources(void);
+extern void func_LdrFindResource_U(void);
 extern void func_LdrLoadDll(void);
 extern void func_load_notifications(void);
 extern void func_NtAcceptConnectPort(void);
@@ -159,6 +160,7 @@ const struct test winetest_testlist[] =
 
     { "DllLoadNotification",            func_DllLoadNotification },
     { "LdrEnumResources",               func_LdrEnumResources },
+    { "LdrFindResource_U",              func_LdrFindResource_U },
     { "LdrLoadDll",                     func_LdrLoadDll },
     { "load_notifications",             func_load_notifications },
     { "NtAcceptConnectPort",            func_NtAcceptConnectPort },