The following tests are commonly used to determine the authenticity of a Pashmina shawl:

1. Burn Test: A genuine Pashmina shawl should feel soft and silky, and should also burn slowly and emit a smell similar to burning hair.
2. Stretch Test: A real Pashmina shawl should have some give and should be able to stretch slightly without losing its shape.
3. Fiber Test: The individual fibers of a genuine Pashmina shawl should be very fine and soft, and should easily separate from one another when pulled.
4. Weave Test: A real Pashmina shawl should have a tight, even weave, with no loose threads or holes.
5. Weight Test: A genuine Pashmina shawl should be lightweight and airy, despite its large size.

It is important to note that these tests are not foolproof, and that there are many fake Pashmina products available on the market that may pass one or more of these tests. To ensure that you are purchasing a genuine Pashmina shawl, it is best to purchase from a reputable retailer or vendor and to look for a certificate of authenticity.