ws2_32: Add a test for GetAddrInfoW.

dlls/ws2_32/tests/sock.c

@@ -2764,6 +2764,7 @@ static void test_WSASendTo(void)
 static void test_GetAddrInfoW(void)
 {
     static const WCHAR port[] = {'8','0',0};
+    static const WCHAR empty[] = {0};
     static const WCHAR localhost[] = {'l','o','c','a','l','h','o','s','t',0};
 
     int ret;
@@ -2780,6 +2781,15 @@ static void test_GetAddrInfoW(void)
     ret = pGetAddrInfoW(NULL, NULL, NULL, &result);
     ok(ret == WSAHOST_NOT_FOUND, "got %d expected WSAHOST_NOT_FOUND\n", ret);
 
+    result = NULL;
+    ret = pGetAddrInfoW(empty, NULL, NULL, &result);
+    todo_wine
+    {
+    ok(!ret, "GetAddrInfoW failed with %d\n", WSAGetLastError());
+    ok(result != NULL, "GetAddrInfoW failed\n");
+    }
+    pFreeAddrInfoW(result);
+
     ret = pGetAddrInfoW(localhost, NULL, NULL, &result);
     ok(!ret, "GetAddrInfoW failed with %d\n", WSAGetLastError());
     pFreeAddrInfoW(result);