twain_32/tests: Generate an error and skip instead of assert()-ing when the setup fails.

dlls/twain_32/tests/dsm.c

@@ -18,7 +18,7 @@
  *
  */
 #include <stdarg.h>
-#include <assert.h>
+
 #include "windef.h"
 #include "winbase.h"
 #include "wingdi.h"
@@ -33,6 +33,7 @@ static DSMENTRYPROC pDSM_Entry;
 static BOOL dsm_RegisterWindowClasses(void)
 {
     WNDCLASSA cls;
+    BOOL rc;
 
     cls.style = 0;
     cls.lpfnWndProc = DefWindowProc;
@@ -44,9 +45,10 @@ static BOOL dsm_RegisterWindowClasses(void)
     cls.hbrBackground = GetStockObject(WHITE_BRUSH);
     cls.lpszMenuName = NULL;
     cls.lpszClassName = "TWAIN_dsm_class";
-    if (!RegisterClassA(&cls)) return FALSE;
 
-    return TRUE;
+    rc = RegisterClassA(&cls);
+    ok(rc, "RegisterClassA failed: le=%u\n", GetLastError());
+    return rc;
 }
 
 
@@ -832,7 +834,11 @@ START_TEST(dsm)
     HANDLE hwnd;
     HMODULE htwain;
 
-    if (!dsm_RegisterWindowClasses()) assert(0);
+    if (!dsm_RegisterWindowClasses())
+    {
+        skip("Could not register the test class, skipping tests\n");
+        return;
+    }
 
     htwain = LoadLibraryA("twain_32.dll");
     if (! htwain)