The collection of books included in what is commonly called the “New Testament” includes four Gospels, a vision, a documentary on the acts of the apostles, and several letters.
A collection of writings is just an arbitrary choice. It is in no way a “testament” of anything.
If you think there is a testament in there, give a reference to where.
This is the “New Testament:”
Jeremiah 31:
[31] Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah:
[32] Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD:
[33] But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
[34] And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD; for I will forgive their iniquity, and I will remember their sin no more.
Note that this new testament is with the House of Israel, and The House of Judah, not with any imaginary "church." .