Plumbing system test fitting

A test fitting for testing a plumbing system, said fitting comprising:

• a body including a bore formed therein and defining a flow passage, said body being adapted to be connected to a conduit at opposite ends of said body for insertion in a plumbing system, said body including a first lateral port opening into said bore and a second lateral port spaced from said first lateral port for connecting said body to a source of test fluid for said plumbing system;
• and
• a flexible molded polymer diaphragm assembly disposed in said bore and including a pull member extending through said first lateral port, said diaphragm assembly including a peripheral rim part adapted to be retained in said bore and a generally circular thin walled diaphragm part joined to said rim part, the diameter of said diaphragm part being greater than the diameter of said first lateral port, said diaphragm part being connected to said pull member and responsive to a pulling action on said pull member to be separated from said rim part and extracted from said bore through said first lateral port.