How can you test for 100% wool?
Cut a small piece of the fabric that you want to test and apply some soap or wetting agent and soak until the water penetrates into the fabric.
When it is completely wet through, put in a bowl and pour in simple household bleach until it is totally covered.
Bleach can lose some strength over time, so the more recent the purchase the better.
If the fabric is 100 % wool it will completely disappear. This process should take no longer than 24 hours.
If the fabric contains synthetic fibers there will be a mesh left over.