Is sharing nuclear tests common?
The United States conducted nuclear tests in Nevada openly and with full disclosure in the 1990s on behalf of our U.K. allies. We speculate on Israeli access to the U.S. test results. For their part, the Chinese admitted to having conducted hydronuclear and radiation effects tests for France, but most tellingly they also implied—they certainly did not deny—the test of a Pakistani device. The South Africans also apparently worked with the Israelis on a nuclear test in the South Pacific in 1979. Are Chinese proliferation programs ongoing?
Since 1991, China has been assisting the raw-materials side of the Iranian nuclear program with shipments of uranium, instructions on the design of a conversion facility in Eshfahan, and an enrichment facility at Karaj. China has been using North Korea as the re-transfer point for the sale of nuclear and missile technology to Iran, Syria, Pakistan, Egypt, Libya, and Yemen. You also write that Israel was given assistance in developing their bomb while the United States looked the other way.
In the wake of the Suez crisis in 1956, the French and the Israelis initiated a joint nuclear weapons program that resulted in a test in the Algerian desert. At that test in 1960, two countries went nuclear with one shot. Is the world safer or more dangerous with all these powers?
The world is safer for having all the permanent UN Security Council members possess nuclear weapons. I think having North Korea, Pakistan, and India is probably not a good idea. Nuclear proliferation, above all, is not inevitable as many thought at the dawn of the nuclear age.