title: need help using anchor frmaework
body: <p>i need help solving this using Anchor Framework. can anyone help? thanks :D</p>
  <ol start="2">
  <li><p>Write test cases to prove that the contract is functioning as expected in anchor.Write sample program with the following specs:</p>
  </li>
  <li><p>State variables:</p>
  </li>
  <li><p>Merchant</p>
  </li>
  <li><p>Buyer</p>
  </li>
  <li><p>Price</p>
  </li>
  <li><p>Constructor:</p>
  </li>
  <li><p>Can be initiated only by the merchant</p>
  </li>
  <li><p>Pricing function:</p>
  </li>
  <li><p>Create price of product</p>
  </li>
  <li><p>Pay:</p>
  </li>
  <li><p>Calculate current gas fees on blockchain.</p>
  </li>
  <li><p>Add current gas to price of product.</p>
  </li>
  <li><p>Take payment from msg.</p>
  </li>
  <li><p>Withdraw:</p>
  </li>
  <li><p>Let ONLY merchant withdraw the proceeds of sales from the contract to his wallet.</p>
  </li>
  <li><p>Write test cases to prove that the contract is functioning as expected in anchor.</p>
  </li>
  </ol>