You can test your own soil! Take two separate cups and add your soil sample to each. In one add vinegar and the other add some water, stir and add baking soda. If nothing at all happens your soil is some what PH balanced.
Eggshells are a great addition to your gardening plans. Here's how to incorporate them to boost soil, deter pests, and (hopefull Place crushed shells in dirt mix, on top to deter slugs + in compost to increase yields.