A more thorough explanation:

The Test Act was a law in England that required anyone holding a public office or position of trust to be a member of the Church of England, swear an oath of loyalty to the king or queen, and sign a declaration against transubstantiation. This law was passed in 1673 and was in effect until it was repealed in 1828.

For example, if someone wanted to be a member of Parliament or hold a government job, they had to be a member of the Church of England and swear loyalty to the king or queen. This meant that people who were not members of the Church of England, such as Catholics or nonconformists, were excluded from holding these positions.

The Test Act was a way for the government to ensure that only people who shared their religious and political beliefs could hold positions of power. It was a controversial law that discriminated against religious minorities and was eventually repealed due to pressure from those who believed in religious freedom and equality.