Are Christianity's Claims Testable?

What’s unique about Christianity is also testable, verifiable and viable. Many religions do not make historical claims that if proven false would nullify the ideology. Of the religions that do most, if not all, claim historical events that happened in unverifiable ways, such as occurring at private locations. In those religions, it is usually one person who dictates to the public the truth claims and the private confirming event.
For example, Mohammed received his spiritual validation from an event that happened privately. He claimed that he was visited by the archangel Gabriel in a cave called Hira on the Mountain of Jabal an-Nour. He was the only one that experienced this, and was the singular mouthpiece for spreading the resulting Quran. This makes his claim impossible to verify, or disprove. It may have happened, it may not have happened. We don’t know because if it did happen it was in private. All we are left with is our ability to judge the words from the Quran. Do they seem to fit with what a creator God might be like? It’s all very subjective when the verifying event is done in private. 
This is the case with other known world religions. Someone may be visited privately by an angel, or receive a private dream, or have a private idea. Since these events can’t be verified empirically or historically, they must be judged based on the moral code they present. So for this reason, any religion or worldview that appears under these kinds of private circumstances are very difficult to verify. All we are left with is to judge whether the morality being taught seems valid. 
Christianity is different on two counts from all of these religions, ideologies, and especially Secular Humanism. First, it makes historical claims, which if falsified, would prove the religion itself false. Graham Stanton said it this way, “The gospel is concerned with history: not in that it stands if its claims could be verified by the historian, but in that it falls if the main lines of the early church’s portrait of Jesus of Nazareth were to be falsified by historical research.”⁠1 If Christianity’s historical events could be proven to never have existed, Christianity itself would be nullified. 
Even Jesus pointed to this difference when he identified that people have differing levels of verification needed to believe in him. Jesus said, “Believe Me that I am in the Father and the Father in Me, or else believe Me for the sake of the works themselves.” (John 14:11) Jesus, here, gives two orders evidence that can lead to belief. He implies that some will believe in him simply because of his words. Nathaniel, in the first chapter of the Gospel of John, is an excellent example of this. This is related to what I said previously about believing by way of examining the moral code, and the words spoken. If this were the only kind of verification that Jesus could offer the world, then Christianity would not be any more verifiable than any other religion. 
However, Jesus gives a second order of verification. He points out that there are those who will find it hard or impossible to believe his words alone. They need more proof. The disciples were initially skeptical of Jesus’ resurrection. When they were first told, they needed to go see the empty tomb for themselves. Thomas, one of the twelve disciples, was one who needed to see even more evidence first hand. In the 20th chapter of John he does. He gathers empirical data on the risen Jesus. At the end of this encounter Jesus says, “Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.” (John 20:29) Once again, here, Jesus shows that there are two levels of verification by which belief may come. Some will believe because of Jesus’ words, and some will believe because they see the evidence. Fortunately for all those who lived after the life of Jesus, there are well documented accounts of the things that Jesus did publicly. 
These historical events pertaining to Jesus’ story were done in public, and instead of one person relaying their message, the multitude of eye witnesses communicated the message to a larger public. This matters because the stories of Jesus were spread in a time when thousands of eyewitnesses were still alive and able to corroborate or deny the supernatural claims. 
Jesus was publicly announced by the famous prophet John, he publicly did miracles, he publicly taught, he was publicly executed, and publicly appeared after his death. Despite all of the audacious claims, there are no contemporaneous writings that claimed he did not at least exist and do miracles. 
Even his opponents, the Jewish religious establishment, claimed he was a sorcerer as written in non-biblical sources like the Talmud, with statements like, “Jesus the Nazarene practiced magic”⁠2 They meant it as an insult, because magic was forbidden, however by trying to destroy his reputation, they confirmed his supernatural ability. There is no reason why they would admit that he did magic if they could avoid it. 
The basic historical claims of Christianity are well established by the historical method. Agnostic New Testament scholar Bart Ehrman, in speaking of Jesus, says, “He certainly existed, as virtually every competent scholar of antiquity, Christian or non-Christian, agrees, based on clear and certain evidence.”⁠3 This means that Christianity can be tested historically, something of which Secular Humanism, atheism, and many other world religions are incapable.

1 Stanton, Graham. Jesus of Nazareth in New Testament Preaching. London ; New York: Cambridge University Press, 1974. p. 189
2 Peter Schäfer, Jesus in the Talmud. Princeton, N.J.: Princeton University Press, 2007: 35

3 Ehrman, Bart D. Forged: Writing in the Name of God--why the Bible’s Authors Are Not Who We Think They Are. Reprint ed. Bravo Ltd, 2012: 285