Most testing labs with a CWI or a SCWI on staff should be able to certify you. However, you need to be very specific with your request and the information you provide them in order to get the performance test you need.
You should provide the lab with the following information, etc.:
1. The applicable code, i.e., AWS D1.1, AWS D1.5, AWS D17.1, ASME Section IX, API 1104, etc.
2. The welding process. It would be nice to use the proper terminology, i.e., Shielded Metal Arc Welding, Gas Metal Arc Welding (and transfer mode: short circuiting, globular, spray, or pulsed spray), Gas Tungsten Arc Welding, etc.
3. Base Metal, i.e., carbon steel, high strength low alloy steel, austenitic stainless steel, aluminum, etc. and the specific alloy type: A36, A572 Gr 50, 6061-T6, 304 SS, etc.
4. Product Form, i.e., plate or pipe
5. Thickness and diameter (if welding pipe)
6. Position
7. You should provide them with a Welding Procedure Specification (if you have one). All welding standards require the welder to follow a WPS when testing. Some welding codes require the WPS to be qualified by testing (example: ASME Section IX).
8. Provide your own material with proper identification, i.e., material test report are great if you have a copy.
9. Provide your own welding machine and filler metal so you don't have to work with a machine you are unfamiliar with and electrodes you don't prefer.
The more you know about the test you want, the more likely you will be satisfied with the paperwork the lab generates.
Different codes have different requirements. Likewise, different employers or customers work to different codes. There is no one welding test that covers all the welding codes and standards used by different industries.
Most of my time on the telephone with new clients is spent finding out what they really need. It is amazing how many clients don't know what they need or want. I've had companies tell me they want their welders to be qualified for everything. I tell them they don't have the money and I don't have enough years of life in me to accomplish that goal, so let's narrow the scope a little.
Best regards - Al