Will a disbeliever who died without the message of Islam reaching him be tested on the Day of Resurrection, or will he enter Hellfire directly, especially in the context of the hadith which mentions that 999 out of every thousand will enter Hellfire, and 998 of them will be from Gog and Magog?

He who dies without the call of Islam reaching him will be tested on the Day of Resurrection. As for Gog and Magog, they are disbelievers and their destiny is Hellfire. He who received the call of a messenger before Islam, disbelieved in it, and died upon that state, he will be in Hellfire like other disbelievers. The authentic Hadith mentions that out of every thousand, nine hundred and ninety-nine will enter Hellfire. The Prophet, peace and blessings be upon him, explained this by saying that a thousand are from Gog and Magog, and one is from his Ummah. He then gave glad tidings to the Muslims that they would be a quarter of the people of Paradise, then a third, then half.