riched20/tests: Simplify the check for an empty string (PVS-Studio).

dlls/riched20/tests/editor.c

@@ -3736,9 +3736,8 @@ static void test_EM_SETTEXTEX(void)
   
   ok (result == 1, 
       "EM_SETTEXTEX returned %d, instead of 1\n",result);
-  ok(lstrlenW(buf) == 0,
-      "EM_SETTEXTEX with NULL lParam should clear rich edit.\n");
-  
+  ok(!buf[0], "EM_SETTEXTEX with NULL lParam should clear rich edit.\n");
+
   /* put some text back: !ST_SELECTION && Unicode && !\rtf */
   setText.flags = 0;
   SendMessageA(hwndRichEdit, EM_SETTEXTEX, (WPARAM)&setText, (LPARAM)TestItem1);
@@ -5225,8 +5224,7 @@ static void test_EM_STREAMIN(void)
   result = SendMessageA(hwndRichEdit, WM_GETTEXT, 1024, (LPARAM)buffer);
   ok (result  == 0,
       "EM_STREAMIN: Test 2 returned %ld, expected 0\n", result);
-  ok (strlen(buffer)  == 0,
-      "EM_STREAMIN: Test 2 set wrong text: Result: %s\n",buffer);
+  ok(!buffer[0], "EM_STREAMIN: Test 2 set wrong text: Result: %s\n",buffer);
   ok(es.dwError == -16, "EM_STREAMIN: Test 2 set error %d, expected %d\n", es.dwError, -16);
 
   es.dwCookie = (DWORD_PTR)&streamText3;
@@ -5237,8 +5235,7 @@ static void test_EM_STREAMIN(void)
   result = SendMessageA(hwndRichEdit, WM_GETTEXT, 1024, (LPARAM)buffer);
   ok (result  == 0,
       "EM_STREAMIN: Test 3 returned %ld, expected 0\n", result);
-  ok (strlen(buffer)  == 0,
-      "EM_STREAMIN: Test 3 set wrong text: Result: %s\n",buffer);
+  ok(!buffer[0], "EM_STREAMIN: Test 3 set wrong text: Result: %s\n",buffer);
   ok(es.dwError == -16, "EM_STREAMIN: Test 3 set error %d, expected %d\n", es.dwError, -16);
 
   es.dwCookie = (DWORD_PTR)&streamTextUTF8BOM;