Are nuclear weapons tested in space?

It is possible to test a nuclear weapon in space, but it is banned.

Nuclear weapons have been exploded in space. In 1962 starfish prime test exploded a 1.4 megaton bomb (~100 times bigger than the Hiroshima bomb) was detonated 400 km over the central pacific. The electromagmetic pulse (called an EMP) damaged communications and electronics from Hawaii to New Zealand (a distance of 7000 km). If this was done today it would cause billions of dollars in damages by wiping out computer systems and satellites over an area of millions of square kilometers. The gamma energy of a nuclear weapon is normally turned into heat when exploded in the atmosphere but in space there is no atmosphere to heat up so all the gamma energy is turned into an EMP that fries electronics. Just one bomb exploded over the United states at 500 km would destroy all computers and electronics that were turned on at the time in the entire country. Military electronics are hardened against this.