There are any number of pump suppliers for that service. You should have no trouble finding them using the search words "water pump" on the web. Use WWW.GOOGLE.COM or any other search engine.
There are a large number of possible pump configurations you could use so it is a good idea...
You should give more information on the pipe you wish to test and the service it will be in. All important pipework is designed, installed and tested to a reputable code these days and the relevant code (of which there are many) normally specifies the pressure that the pipe must be hydrotested...
My contribution.
Concerning the strength of a socket welded joint. At any location in a piece of pipe there are three stresses to consider: (1) the hoop stress caused by pressure in the pipe, (2) the longitudinal stress caused by pressure in the pipe and (3) bending stress caused by forces...
